I kind of have the feeling that the only character from Shenmue II to make a return in Shenmue III would be Shenhua (other than Ryo of course). I also think that Shenmue III (this is all assuming that more than three Shenmue games are made) would take place entirely in Guilin. I wouldn't be surprised if characters like Nozomi, Ren, Gui Zhang, Joy, Xiuying, et cetera never made another appearance in the games, but I don't know much at all about Yu Suzuki's plans or anything and haven't done much research (any) so I'll probably be told I'm wrong pretty fast :lol:
These are all just hunches, gut feelings, I don't really have any way to back them up...