Yes, as someone else suggested, I wouldn't mind seeing Luke as the "Obi-Wan" character. Leia, Lando, Han and Chewie could work well in the background or maybe only one scene or so. I can see a problem with trying to shoehorn in EVERY character, such as Force Ghosts Yoda, Obi-Wan, Anikan, etc...
Yeah, I wouldn't want every
OT character thrown in there, but I'm okay with Han, Chewie, Luke, and Leia (although from her recent "open letter", it sounds like Fisher will probably be the one hold-out).