Diablo 3 Three player group - optimal setup?

So we are having a four day LAN when d3 is released, and we want to be somewhat efficient in our pick of classes. Due to examination periods/work we have not been able to do as much beta-playing and online research as we would have liked, so I figured I would ask my questions here where a lot of people know pretty much everything you could possibly know about the game at this point in time.

- We will be playing three people for four days straight after release, if possible we want to reach inferno (reach, not planning on clearing it four days after release) and have a somewhat good setup for clearing it in the future. One person is dead determined on playing a barb while the other two of us will play whatever is best for the group. Which classes would this be, and are those classes using different stats/gear so that we have a better option of gear while levelling up?

- Would we possibly benefit a lot more from including a fourth player via the internet/realID, considering we are only three at the LAN, but are considering the extra abilities a fourth, unique class could bring?

- How important is crafting during the actual levelling process to 60? Will it not be just fine to go back and pick it up after you reached the maximum level?

All I'd really go for is classes that use different gear (e.g. WD and wizard both use int gear, DH/Monk both use dex). Even though drops are individual you can all share loot together and get 3 chances at upgrades off every boss/rare mob.

Outside of that its all preference, the monk can heal a little bit but its also melee like the barb. The DH is great ranged damage. Wizard has a bit of CC and other control effects, but the WD can make an army to occupy mobs too. Just play what you like and enjoy the game, It will be around for years!