Just some random thoughts on this topic. FFG seems different than Decipher in that every single character to get 2 seconds of time in the movies doesn't get a character but I think we may get some.
Here's my 2 cents
BIggs - Obviously a Rebel Pilot of some sort.
General Dodonna - Rebel leader. I could see him getting made.
Uncle Owen and Aunt Beru - Jedi support units maybe?
General Tagge - Imperial Navy clearly
Admiral Ozzel - How to make a card based on a guy so stupid you want to kill him yet he's still playable? Again for the Navy
I could see Ree Yees and Tessek getting made as they've had figures since the old days. Scum and Villainy needs someone beyond Jabba, Bib, Salacious and a bunch of Bounty Hunters. Maybe a Rancor Keeper that, when out, protects your side from the Rancor?
Wicket - Not sure how the Ewoks are going to work. Spread out throughout the Light Side factions or a gray series? Chief Chirpa and Logray have a shot at being made as well I'd guess.
Nien Nub - Rebel pilot or Spies and Scoundrels pilot you think?
Sim Aloo - Maybe for the Sith? He had a figure made in the old days and is the Imperial Advisor most people vaguely remember. If not him, then who else from the actual movies could you make for the Sith?
Also regular versions of Piett and Jerjerrod I would guess.
I'm going to guess if we ever get Prequels it will be the Grand Army of the Republic, The Combined Naboo Defenses, The CIS and.............can't see the Trade Federation getting their own faction but who else would you pick?