Maybe I'm treating the question as more specific than it needs to be, but in your example it appears to me as though player 1's agency is being denied. Twice she stated her action clearly, and yet somehow she failed to get the results of that action back from you.
You don't have to wait until all players are agreed before allowing a player to act. Now, OK, you don't want the party to split unless really necessary, but until they're actually out of earshot of each other, let each player get on with what they want to do. Running through your example hopefully will show the principles I mean:
GM: Okay, you're standing on the edge of the forest.
Player 1: Okay, I ready my bow and start forward.
GM: fine
Player 2: Hold on, I'm still talking to this other guy.
GM: Player 1, are you scouting ahead alone?
Player 1: I'll take a look, I won't go far until the others catch up.
Player 3: Did we stock up on bread? I need to put on my night vision
goggles.
GM: If the bread's not on your equipment list then you didn't stock
up [or if that's not your style of game, "yes, you stocked up on usual provisions at the supermarket yesterday"]. You now have your goggles on.
Player 4: [Crazy roleplaying thing!]
GM: [Crazy roleplaying response]
GM: Okay, are you guys going into the forest?
Player 1: I am, yeah.
GM: You start to walking into the trees...
Player 2: One sec, I need to cast detect evil.
GM: No problem, but Player 1 was already doing this while you finished with the other guy and that roleplaying thing happened.
... the undergrowth is mostly pretty thick, but you easily find what
might be an animal trail. You'll be able to travel much faster along
the trail if you want to. Player 2, if you've finished your conversation with the other guy, you cast Detect Evil. Nothing in
range. I assume you maintain it as you start into the forest?
Player 2: of course
GM: You can't see exactly where player 1 is, but she can't have got far. Okay, actions from everybody else?
Principles:
- Stay in the conversation
- Respond to actions and requests for information as quickly as possible. But in the case of Player 1 setting off ahead alone, I think it's also reasonable to give the others an opportunity to react and for Player 1 to confirm before doing something that takes a little while and might be foolish. You don't want a conversation that goes, "1: I ready my bow and start into the forest, "2: hang on a sec...", "GM: 1, you fall in a spiked pit and get ambushed by 40 goblins", "1: well, actually, I didn't mean I'd leave the party, I was about to say I'd have waited when 2 said to hang on but you interrupted", "GM: Ah. I totally didn't get that from what you said".
- If something can happen, narrate it happening.
- You don't need to design the adventure specially to avoid delays. Once the players get used to the style, they can keep the action going just by acting. Or they can stop when they really need to, they're in control.
- Don't ask the players what's happening. Ask the players what they're doing, tell them what's happening.
Now, there's a whole other scenario you have to be able to deal with:
GM: Okay, you're standing on the edge of the forest.
Player 1: Okay, I ready my bow and start forward.
All other players: WAIT!!! We need to make a plan.
Player 2: Also, I'm still talking to this other guy
GM: Player 1, are you scouting ahead alone?
Player 1: No, I'll stick with the others until we have a plan.
All players: refuse to move while they spend 30 minutes arguing the
best tactics for hiking.
In this case you have mass analysis-paralysis. There are a few ways to break it:
Specifically tell the players that their precise plan doesn't matter. As soon as any encounter begins you will prompt them for their formation, and you will allow for sensible precautions. This doesn't suit all playing styles, but it saves a lot of time making preparations for things that never happen. The game style issue you want to resolve is, will the players be punished for acting without thorough explicit preparation? If so, then that might be why Player 3 is worried about bread, and it's the nature of a "10 foot pole to check for traps" game.
An extreme version of this is to run the game such that whatever the players suggest is considered reasonable. The world conforms to their expectations rather than the other way around. Then they don't need to plan at all, and the way to reach group agreement is not to wait until everyone agrees, it's to take turns to speak, and agree with and build on whatever the previous person said. They can improvise, they can take turns to contribute, and no matter how stupid what they do is, you will respond "yes, and...". Not "no, because" or "oh, this other thing first needs to happen first", or "you do that but you die because you never said you'd put your armour on". Again, this won't suit all styles, it's not very simulation-y. But they'll stop doing pointless boring things, because any interesting thing they think of is worth saying.
Guide the players through making the plan. You don't want to give them too much OOC information, but usually the characters have expertise that the players don't, and you can bolster their confidence by confirming their guesses and supplying general information at the right times. Confident people make decisions quicker:
GM: Okay, you're standing on the edge of the forest.
Player 1: Okay, I ready my bow and start forward.
Player 2: Hold on, I'm still talking to this other guy.
Player 3: Did we stock up on bread? I need to put on my night vision
goggles.
Player 4: [Crazy roleplaying thing!]
GM: Alright. Player 1, you're going to scout ahead, and you're ready
for trouble, that's sensible. Player 2, sorry, the other guy really
doesn't have anything else to say. Player 3, yes, you're fully
stocked, the night vision goggles will negate the darkness penalty
under the trees. Player 4, I like your style. Do you all fall into
formation behind player 1?
[In your transcript, at this point you said "are you guys going into the forest?". That is to say, you asked the group for a consensus before giving them any feedback on their individual issues. If you do that a lot, it's probably the main reason things get stalled.]
Player 2: One sec, I need to cast detect evil.
GM: I'm fine with that if Player 1 will wait?
Player 1: For one round? Sure.
Player 3: I'll stick close behind Player 1 since I have the best
sight.
GM: Good. 2, Results of Detect Evil are [whatever]. 4, once you're
done invoking the wrath of Gragnar on any fool who dares oppose you,
where are you in formation?
Player 4: Rear-guard, if everyone's happy with that. The Book of Gragnar commands us to, "Pity especially the fool who tries to sneak up you in a forest".
GM: Sounds good. Doing that thing you normally do when you're
rear-guard? That leaves player 2 in the middle. Onwards!
Design adventures so that the party doesn't have a lot of time to waste. You don't have to railroad, but make sure that there is always something happening to them. They can deal with it however they like, but they must act. After all, arguably if there's nothing happening to them and they're free to delay as much as they like then that's practically the definition of "downtime between sessions" ;-) So, players don't arrive at the edge of a forest at their own leisure, they arrive at the edge of a forest as a consequence of dealing with the previous problem:
GM: Okay, you're standing on the edge of the forest. You can hear those
enraged villagers with pitchforks approaching, but as you already know
they're very superstitious about the forest, and you suspect they
probably won't enter it this close to dark.
All players: start to plan
GM: [after a couple of minutes or so, representing the party's head start] The villagers have crested the hill behind you, and the front few break into a run. They're in missile range and will reach you in a minute or less, but then again you never thought much of their combat ability.
All players: No, we're not slaughtering the whole village! We get into the forest.
Finally, be aware that "keeping the game moving" doesn't need to mean physical activity or plot progression. If Player 4 goes off on a crazy roleplaying thing that the other players react to and enjoy, then it's irrelevant that it isn't part of your plan for the session. It's as much a part of the game as anything you invent. So encourage it to play out properly, and as long as it's not boring the forest can wait. Similarly, if the players just plain enjoy bickering in character over their plans, you can let that be part of what defines that particular campaign. Just build 20-30 minutes per significant group decision into your session plan. Less work for you!
To do this you need to get buy-in from the "more action-oriented players". If all they like is combat then that's pretty much a non-starter, you can't run a game this way for them. But otherwise you need to stop them tuning out by soliciting their responses, and making those responses matter in the conversation. A frustrated character who spends the whole argument saying, "we need to stop arguing about this and get into the forest" in 10 different ways is still an active player. One trick is to keep track of who is speaking, and if someone hasn't spoken for a while specifically ask them, "what do you think, what are you doing while this is going on?". That gives the player the freedom to take a turn in the conversation, or for that matter to wander off into trouble if they like. If you frequently find that you ask a player what they're doing and they say "nothing" and tune back out again, then you still have a problem and need to address personally with that player what they need from the game. Some players enjoy spectating for some of the time, and might look tuned out when they aren't, so you do need to ask.
It all comes down to agency. What choices are the players making?
If you are spoon-feeding them encounters, which they have no options but to engage, then yes, it's on you to make sure those encounters are survivable. If they are choosing what to do and what to engage, then the responsibility lies on their heads, not yours.
Let's look at two possible situations.
Situation 1
The PCs are in camp when some raiders attack. Oh noes! They wake up, but the raiders are surrounding them. They have no choice but to fight the raiders, and they are of such number and ability that at least one PC death is, essentially, inescapable.
Situation 2
The PCs are in a town when it is about to be attacked in force. They can stay and help the town defense, in which case it may stand. They may also flee the town, in which case the attackers will almost certainly win.
However, the attackers are of such force and number that if the PCs decide to stay and defend the city, it is highly likely that at least one of them will die.
Choice is the difference
In both of these scenarios, the PCs are faced with a fight that they might not survive. However, in the second one, they choose to get involved in that fight. It is their choice to risk their PCs to keep the town standing (or not). Not only does this put the responsibility on their head, but it also gives them a chance to be truly heroic. These types of choices (what am I willing to risk?) are some of the best moments in roleplaying, especially when real risk is on the table.
It's okay for PCs to die! But they should do so as a result of choices they make, not encounters that the GM "throws" at them.
Try a Clock
For the specific case in the OP, consider something like an Apocalypse World front's "clock". As the PCs engage in activities that will cause unwanted attention, you can increase the "clock" and the tension/heat that the players will encounter. This gives them an idea of the seriousness without making it an immediate "you die" moment. It also gives them the choice to continue with what they're doing or not.
So, for the "heresy" clock, the stages might look like this:
Stage 1: Mutterings of heresy. Some of the townsfolk talk about a new heresy they've been hearing.
Stage 2: Known heresy. People talk about this crazy new heresy they've heard about, with specifics.
Stage 3: Official pronouncements. There are proclamations that the heresy is in fact against the church.
Stage 4: Public trials/executions. Heretics are found and imprisoned or killed.
Stage 5: Manhunt. Wanted posters are put up for the lead heretics (aka the PCs). Movement becomes difficult.
Stage 6: Assassin squads. Exactly what it says on the tin.
You can then advance the current stage based on time or PC actions. This will give the impression of advancement and real change in the setting, give enough of a social movement to warrant the church's actions, and, perhaps most importantly, give the PCs plenty of warning that continuing on this path will result in dramatic consequences.
And that may be cool! This kind of "heresy plotline" may be exactly what the players want, and so letting them play through that may totally make them happy.
Best Answer
Suggestively and Subjectively, If At All.
Based on your reference to Neverwinter, I am assuming that this is some version of Dungeons and Dragons, which has no general mechanic for this sort of thing, only specific mechanics for things like Cause Fear spells. I also recognize you're not talking about those special spells or spell-like effects.
The general guidance here is, "Don't. Really, don't." In Dungeons and Dragons-like games, this is an often-unwanted intrusion into the player/character agency, as you rightly recognize in your question phrasing.
Even so, I understand the desire to provide this kind of guidance, and there are situations where it can be appropriate, and one technique I have had some success with:
If your players ask, then by all means give the mood-setting guidance you want to give. I've had this happen a number of times where the player will just up and ask me if his characters thinks or feels a certain way. Surprises me every time, because that's not how I play my characters, but it does happen.
You can skirt the issue in a number of ways, with a number of semi-weasel grammatical constructions, many of which boil down to use of the subjunctive mood. What the subjunctive does, in so many words, is express something hypothetical or something assumed, inferred or implied, but not really known to certainty. So I found myself saying things like, "You might be feeling the hairs on the back of your neck standing up, right about now," or "Most people would be revolted by this." Those phrases can be highly suggestive and evocative, providing clear mood, tone, and guidance, but they don't actually take the agency away from the character. The player can always decline that hypothetical, and they are somewhat prompted to accept or decline, almost required to do so in a way. I found it very effective once I realized what I was doing and was able to do it on purpose.
(Having worked so hard at it so long ago, my high school Latin teacher would be so proud of me, right now. Next week's lesson: Ablative absolute, or, "You too, can sound like Julius Caesar in two easy words.")