I noticed there is a force awakens set. Does that mean there will be 5 groups in total to play as? (Rebl, Imperial, Sum, First Order, Resistance) Or do the F/0 and Resistance ships get rolled into empire and Rebel forces?

Do the individual X-wing and TIE Fighter expansions offer any new cards that the core set doesn't give you with thier X-wing and TIE Fighter?

Resistance is a subset of the Rebels and FO is a subset of the Empire; you can play mixed squads.

There are a few cards in the separate expansions worth getting, including some additional pilots.

ok cool. I'm trying to collect all the Rebel, Imperial, and Scum ships, but didn't want to get any force awakens stuff if those 2 were the only ships for those sides

You should check out the wiki for various (and precise) lists of what's in each expansion pack. It can be a really helpful resource.

http://xwing-miniatures.wikia.com/wiki/X-Wing_Miniatures_Wiki

So far it's just the T-70 and TIE/fo for those sub-factions. Assume we'll get more as movies get released. And yes, definitely check out the Wiki as Critias has suggested.