In the prequels, there are plenty of characters who play bit parts, whom Sally took control of. C3PO and Chewbaccha are both fairly regular characters in the original series, so both having players makes sense. Really, the only main character who croaks it partway through is Obi-Wan, suggesting that Ben might be the one to play several secondary characters - perhaps first switching to Biggs and finally settling in as Lando. Sally will probably play as Yoda, while C3PO is broken.
That would probably leave us with:
Jim as Leia, the current GM as Luke, Sally as C3PO (or possibly Chewbaccha), Ben as Obi-Wan, Pete as R2-D2 and noone playing Han or Chewie. Given how those two are introduced together, perhaps this will be a new pair of players - Chewie as a the creation of a somewhat different munchkin than R2-D2.
Under this theory, we would get two new players, unless some played several characters. Of course, Annie as one relatively new to GMing might have Han be a reviled GMPC, I suppose. Then again, perhaps she will succeed in making the rare 'likable GMPC' and be surprised when the players elect to risk their lives to save him after she writes him out.