Is the problem laziness or lack of skill?
This problem can be approached in either of two ways: treat the symptoms or treat the disease. I would attempt both of them, in that order.
Treat the symptoms: aka How do I Rogue?
As a core class, the Rogue is in the SRD. Given your party's use of digital means this should not be a problem to use. Character sheets do not have space to write the rules of a class feature, but here they are listed for your use. Ask of your players that need to that they write down their class features, feats, skills and magic items and what they do. This way they have the rules on hand at all times. Make them aware what these things can do for their character and the party.
Even then, there's something of a problem. The party consists of one melee guy, two casters and the Rogue. This means that the Paladin is going to be bearing the brunt of the melee attacks, and can easily be swarmed. While there's a good chance to flank a guy fighting the Paladin, the moment that the attacker drops the Rogue is out in the open. This is NOT a good thing for a Rogue with their light armor and d6 hit die. Make the player aware of this, preferable before combat with a large group.
The cure: how lazy is the player?
The real question: is the player really lazy? Sure, they might have joked about this but it can mean that they are insecure. The biggest clowns are the saddest clowns, after all. Ask them, in private without the other players knowing, if they would like help. Do not make it a confrontation or an accusation: make it an offer and a gesture of good will. Perhaps they do not know how to play a Rogue. Hell, I know that I could not Rogue to save my life. Players who are insecure are not the best teachers either: their mistakes will carry over to the others. Offer to take on the mantle of the sorceror's mentor (try saying that three times quickly) so they can focus on their Rogue.
On the other hand though, if they actually ARE being lazy, tell them that they need to put some time in the books to actually play. You (and few people do) do not like to be bogged down by the player unwilling to learn the rules, as opposed to one who just does not know them. Tell them what you expect of them and when you do so. When this time comes, ask if they managed to do the thing you asked. If they did, great! If not, ask if they need more time or some help (NEVER ask "why not?": this helps nobody).
If they are consistently unable to do so or learn the rules, you should ask them (in private!) if they want to play D&D, or if they would rather be doing something else. If this is the case, shake hands and go your own ways.
Prevention!
You want to start immediately when everyone's at the table. That's fine, but it needs preperation. Ask your players to send in their character sheets for you to check if they are what you expect (do not call it "did it right": this makes you look like a jerk). If everything is fine, great! If not, send feedback. If characters are written digitally ask for prints: if they're filled out by hand ask for pictures (you have WhatsApp, so you likely have phones with cameras). Also ask for the "cheat sheets" that you would like to see of some people. This is not a lot of work: just copypaste from the D20 SRD.
Final advice: Relax!
These events seemed to have rather vexed you. Take a deep breath, have a talk with your players and go and have fun the next time you gather for a game. If the DM is not having fun, it will be difficult for the players to have fun.
First off, these things sometimes happen. If this is a one-off occurrence, I wouldn't be too concerned: people sometimes get it into their heads that they need to do something "weird" for no good reason. I was playing in an In Nomine game as an angel who could possess people/animals; I somehow decided that I needed a monkey, and we spent about as long planning a zoo heist (that never happened).
So, one-off: don't worry too much.
If this is a more common event, or if it looks like it might be (Tom sounds like he might encourage this kind of "weird strategy" thinking), there are a couple of things that have been helpful in my games:
talk to the "problem" player(s): remind them nicely (and privately) that there are other players who need to be included in the action and the planning. yes, this is the default answer to anything with the problem-players or problem-gm tags; it's the default answer for a reason.
remind the players that time is passing in-game. In this particular example, while Tom and Frank were discussing what to do with the interlopers, the captain could be struggling against his bonds, the captors could be rummaging around the cargo hold, a sailor could be whimpering behind a crate. As the planning session goes on, the captors might get more violent, roughing up a sailor who gets in their way. D&D does encourage some "free action" tactics talk among the players, but time does flow.
if they still don't get the hint, a brigand could actually accost the PCs: demanding money, ordering them around, etc.. Roll for initiative! And, remember that the brigands are totally getting a surprise round (are those still a thing in 5E? Sorry, my experience is almost all 3.5/PF). I'd encourage relaxing some of the rules about how long talking-type resolutions take (or, at least, suspend initiative if someone rolls well enough to warrant a brief cease-fire), but there comes a point where conflict is inevitable (this is a good thing: the whole point of RPGs is resolving conflict) and the PCs can't just talk amongst themselves any longer.
alternatively, poll the players to see if they want to continue with strategy or move into action. Tom and Frank can talk about tactics all they want, but if the cleric steps in to stop the pirates from harming their ship's captain, Tom and Frank will have to respond. This can backfire! Tom and Frank can be angered by the cleric acting "before they're ready"; therefore, I encourage mixing this in with #2: "Tom and Frank are whispering about what to do; Cleric: you see the brigands roughing up the sailor; Druid: they're dumping something unpleasant from the hold into the bay. What do you do?"
I'd personally be hesitant to actually use one, but I've seen suggestions to use a small hourglass (a 30-60 second timer) to let the players discuss how to respond to a new situation before in-game time resumes. The in-universe logic being that the PCs have been traveling together for long enough that they can quickly communicate how to respond to violence with a subtle gesture, where the players need to actually talk.
You'll have to be a little careful to not step on Tom's fun in planning intricate strategy, but that's relatively easy: make sure that there are plenty of encounters where the PCs know what's coming far enough ahead that they can talk for a few minutes in-game before the enemies know they're there.
Best Answer
Establish A Rule Disagreement Resolution Tool for your Table
In my reply to this question, I recommended establishing, before the game session, or before the game while session zero is underway, what the "rules disagreement resolution tool" will be at your table.
The objective of this tool -- or something similar that you need to tailor to your specific table -- is that any "huh, it works like what?" question needs timely resolution and a ruling, so that play may continue.
From your description, you have not established that tool. Before your next session, make clear before play begins that GMs need to have fun too, and that their reaction to your ruling damaged the game and damaged your fun.
* Note: it is desirable to get player buy-in to the resolution tool. Once presented, I strongly recommend that you not run another session until the resolution tool is both decided and accepted by everyone at the table. You should actively solicit the players' suggestions and inputs when finalizing the tool.
With the above in mind, here is an example tool to resolve rules disagreements and keep play moving. This isn't the only way to do it, but I've seen it work very well:
Player disagrees with how something works. Says it works another way.
DM to player: Make your case. (Define time limit. 1 minute, 2 minutes, whatever you are comfortable with)
Player: case made briefly
DM listen ...
DM makes ruling.
Play now continues.
Getting the group to buy in to this (or your similar tool) is the key to avoiding the situation you ran into. It is also a matter of table courtesy (bring this point up as well before play begins the next time): we are here to have fun, not get into emotional arguments nor personal attacks.
Your interpersonal relationship with the persons making the challenge may end up with taking on the character of a test of wills. Unless the whole table agrees with the tool, you'll have this happen again. Get the players' involved in crafting the final form of the resolution tool for your table so that you reduce that element of the problem.
If you can't get that buy in, your instinct to give up on that group of players may be the sad future for this group. But you may be able to heal the wound from that session and proceed with more game and more fun.
A last suggestion: if a given player just won't give up on an argument, get up from the table and declare that it's break time. Immersion is gone for good at that point. Once you've all had a chance to calm down, to reduce the intensity of feeling that arose in that disagreement, it becomes easier to resolve.
Other suggested ways to resolve rules disagreements:
Flip a coin (or roll a die) to pick one of the possible rulings, then move on. After the game, look it up and settle on a most correct answer. (@Thunderforge has seen this work in his games).
@anaximander recommends this rule before the game starts.