Welcome, Data!
I see your questions have been answered already, which is awesome.
Hope you don't mind if I add my 2 cents to clarify/expand on a couple things....
Data wrote: 3. Are we supposed to use the resources on the website to choose classes and things ahead of time, or is that part of the prep phase at the beginning?
As people have said, it's great to look over the resources here on the site, so you'll have a better idea of which classes are available, and what their powers are. When it comes down to it, though, choosing classes is something which usually happens during that 24 minutes of prep time in the Coaching room.
In my experience, it usually goes like this:
People arrive and look through the classes, and the free bag of 10 tokens they got.
Some people voice a strong preference ("I wanna be Rogue! I'm *always* Rogue!") and others a mild preference ("I enjoy healers, so I'd like to play Cleric, but whatever - I'm flexible." OR "I got some Wizard scrolls in my token bag, so I think I'd like to try one of the Wizards") and others have aversions ("Just don't make me play the Bard. Anything but Bard. I refuse to sing.)
It's usually easy to work things out, unless you've got two people who both absolutely desperately want to play the same class. If that happens, the "official" way of dealing with it is that players who are Level 3 or above get priority over Level 2 and below (that's player XP level, not character level) and any further conflicts are resolved with a dice roll.
In practice, however, it often works out that whoever arrived earliest and grabbed the class card ends up playing the class they want. It's not particularly cool to do this, but TIME is of the essence (you've only got 24 mins to get a lot of stuff sorted) and arguing will waste your time... so sometimes the better part of valour is to release your claim on a particular role, and instead focus on party cohesion.
Honestly, the "best"way to sort it out, though, is to see who has a stronger set of tokens for the contested Class. If someone wants to play Paladin and has a good weapon and armor for it, they'll probably contribute more to the party than if the guy with nothing but Wizard scrolls wants to play Paladin.
That said, don't rule out enthusiasm for the role: Sometimes the person for the job is the one who will love the role, and knows it best... and you can always trade tokens so they can be well-equipped for the job.
Which leads to the next question....
4. Sort of related, is it common with a group that you each get your bag of 10 tokens and then like split them up as a group based on what might work better for each person's class? Or is that not possible/not feasible for some reason?!
YES. it is incredibly common to do it that way. The best parties (meaning the ones with the highest chance of survival, and usually the most fun) in the dungeon are the ones who practice cooperation early on!
Sharing tokens - or even giving them away - is a great way to build goodwill in the group, and to make sure your party is as well equipped as possible. You may want to pay attention the the Rare tokens (the ones with red print) and either hold onto those, or only trade them for other Rares (a Rare for a Rare is a pretty common trade.)
When it comes to the Uncommon or Common tokens, however, I tell people not to worry about just giving them away if you feel like it. The Commons are a bit like "land" in Magic. If you play enough, you'll have more of those than you need. Sure, they may be worth a few cents, but teamwork and survival are worth even more, so don't be stingy.
Keep in mind that you can also lend tokens just for the adventure, and ask for them back when the other player is done with them. For some items - like Armor - they only need to be seen by the Coach and recorded, and can be immediately given back to the person who owns them. Weapons do need to be carried through the dungeon by the character using them, and can sometimes be lost, or forgotten when people part ways... so be aware of the risks if you choose to lend those out.
After you play TD a few times, you'll probably end up with a small stash of tokens which you can use to gear up different classes, or lend to players in need. Just keep in mind that time is limited in the Coaching room, and once a Coach writes down the equipment/stats for a class, it's rude to ask them to change things. Coaches hate hearing "Oooh! I forgot that I could loan Joe my Half-plate, so the Paldin's AC should be one more - please change that - and then he's gonna lend his leathers to the Rogue, so change that AC too, and then we've got some robes to give the the Wizard - Change his AC kay? - no, I meant Elf Wizard!"
Not only does it waste time in Coaching, but it makes the Party Card hard to read for the DMs and can slow down combat in the dungeon.
Hope I've clarified some things, instead of making it all more confusing!
- Raven