You know, everyone says Kate Beckinsale for Bastila but I disagree, she's too old. Bastila is young, in her early to mid 20's.
I'd definitely hire Morgan Freeman as Jolee though. That guy ''fits'' the role perfectly. As for Revan, that's a tough one. Christian Bale could probably pull the role off, but I'm leaning more towards Tom Cruise. I've seen some of his movies, and that guy definitely has the potential for the role.
Carth is a hard choice. I would probably hire Raphael Sbarge as Carth. Because he has both the appearance and the voice. And everybody knows Sbarge's voice is epic.
As for everybody else, not sure. The thing is, if your making a movie adoption of a video game, the actors need to look like the characters and they need to fit the ''personality'' of the characters. You can't just go out there and hire somebody to play as Carth. It doesn't work like that. You need to take time with finding actors. George Lucas had quite a hard time finding actors for his movie: A New Hope. And most of the actors in that movie fitted the personality's of the characters. It worked out in the end.