Probably the simplest way of thinking about this reduces down to four basic scenarios, two of which we'll be able to eliminate immediately.
- The players and the GM both think the GM is doing a good job.
- The players think the GM is doing well, but the GM doesn't.
- The players and the GM both think the GM is doing a bad job.
- The players think the GM is doing poorly, but the GM doesn't.
The first two, assuming you are speaking for the entire group, are almost certainly untrue. (The second one seems a little odd, but I've seen it happen. We all know GMing can be hard work, and issues of introversion, stage fright, etc can cause anxiety in the GM even though the players are all fine with the GM's job.)
So the first part of helping to fix this is to figure out which of the second two cases you are actually in. I see signs of both in your description. "you know...a lot about them," seems like something most GMs, even beginners, would realize as an inadequate answer in one sense or another. On the other hand, "Outside of game he seems really excited about his story," possibly suggests that he thinks everything is going fine.
In my experience, people who want to do something well, and realize that they aren't, may be more receptive to criticism than people who think they are doing just fine, thank you very much. The latter case may involve shattering some illusions.
Another important thing to realize is that people get better at things due to experience (which this GM manifestly does not have a lot of) due to research (which you have done but this GM probably has not, as he is new at this) and due to constructive criticism and helpful feedback. Especially in a performative art like GMing, it is hard to know if you are really hitting your target without feedback from the audience, and that feedback is both the GM's responsibility to pick up on, and the players' responsibility to provide, without crushing his ego.
All of that pre-amble leads to a central notion of communicating better with your GM both in-game and out-game, but doing so gently.
In-game, you can do things like:
Ask for more of what you want to see. But that does mean asking rather than telling. In your example about the bugbears, you started with asking but reverted to filling in details, feeding them to the GM and getting ratification. It'll be awkward, and it can be overdone, but getting these details to flow from the GM instead of you is key.
In-game, a few mild pointers on mechanics and craft might help, e.g., "Should we really be making those perception checks ourselves? I shouldn't really know my own roll for that, should I?"
In-game and out-game, as a veteran player and GM who is trying to be a model player, I would try very hard to get myself aligned with what this GM finds interesting. This may very well be confounded by the GM himself, but there may be a dynamic going here, where the GM feels obligated to put filler material (for verisimilitude; for mechanical reasons-- to expend a certain amount of your resources, say; for pacing reasons, etc) but is not actually that interested in it himself. The bugbear example might be a case of that, too-- GM feels obligated to put in filler, you feel obligated to follow up on it, no one is happy.
Out-game, praise what you like. I cannot say this strongly enough, so I will shout: OUT-GAME, PRAISE WHAT YOU LIKE. Your GM is not a mind-reader and there is no better way to get his attention than just telling him, "Man, when X and Y happened, and you described Z doing W, that was just awesome!"
Out-game, depending on your answer to the initial question (does he think he's doing well or not) you can always offer to give him a straight-up set of opinions on what went well and what went bad. But it helps immensely to have a feel for how receptive he is to hearing the downsides, and you should be aware that gentleness goes a long way, here.
Out-game, you can always just ask your GM what parts of the game he finds most interesting, and if there are any things you can do as a player to help focus on the interesting parts.
I think this is pretty cut and dried with just what you have quoted. If you're a Luck Halfling and you roll a 1, you can re-roll it once and use the number. Then if you just don't like any number you rolled, even the re-roll, you can spend a luck point to re-roll (again). One doesn't replace the other, you simply have both features, and both operate exactly as they written.
First Case: Feature then Feat
So if you use Halfling Luck to reroll a 1, can you then decide to use a luck point and still get to choose any of the dice?
Yes.
Example
Let's say you roll to attack, and roll a natural 1. Your halfling luck kicks in:
When you roll a 1 on an attack roll, ability check, or saving throw, you can reroll the die and must use the new roll. (PHB, 28)
You get a, say 5. It still isn't high, so you choose to use your luck feat.
Whenever you make an attack roll, an ability check, or a saving throw, you can spend one luck point to roll an additional d20... You choose which of the d20s is used for the attack roll, ability check, or saving throw. (PHB, 167)
Second Case: Feat then Feature
Or if you use a luck point and that dice rolls a 1, do you reroll it with Halfling Luck and then still get to choose any?
Not quite. The roll is whichever you choose when you use in the feat Lucky. So, you could choose the 1, and then get to re-roll, as per RAW, but you'd have to use the number of that Halfling luck reroll not the previous two.
Example
So, in this case you roll a 3 and use Luck Feat to roll again, you roll a 1.
Whenever you make an attack roll, an ability check, or a saving throw, you can spend one luck point to roll an additional d20... You choose which of the d20s is used for the attack roll, ability check, or saving throw. (PHB, 167)
You choose the 1, specifically to trigger your halfling ability. So, you've now effectively rolled a 1, and get to reroll it:
When you roll a 1 on an attack roll, ability check, or saving throw, you can reroll the die and must use the new roll. (PHB, 28)
Best Answer
Yes, you get to reroll a 1 on the attack roll (but must keep the new roll, even if it's another 1)
The gunslinger's Misfire mechanic is described under the Gunsmith feature:
The various firearms in the Firearms table for the subclass (which replace the optional ones described in the DMG) have varying misfire scores ranging from 1 to 3. The subclass also grants proficiency with these firearms.
The halfling's Lucky racial trait says:
As quoted above, the misfire mechanic is tied specifically to attack rolls. Thus, if you roll a 1 on an attack roll with any firearm, you would normally misfire. However, the halfling's Lucky trait means that if you roll a 1 on any attack roll, you can reroll it and take the new roll. This makes it much harder to misfire.
In fact, if you use one of the firearms with a Misfire score of 1 (a palm pistol or a pistol), it's nearly impossible to misfire; as a halfling gunslinger wielding such a weapon, you would only ever misfire if you rolled a nat. 1 on the attack roll, and then got another nat. 1 when you rerolled it (a 1 in 400 chance).