the actor who wants too much money and will be killed off is Dominic Monaghan. I don't know much about the guy, but can envision him being unhappy with Charlie's role on the show and also thinking he is entitled to more cash since he is a semi-star due to LOTR. My backup candidate would be Matthew Fox, who could think that he should be paid leading man money even though it is an ensemble cast and Jack's importance to the show has diminished over the course of season one. I don't really see that happening with any of the other guys on the show.
I'm no expert on Che Guevara, but I know he was a communist revolutionary who helped Castro come to power in Cuba. If Ana-Lucia is going to be that type of character, then it probably means she becomes a leader of some sort of militant group. That should be very interesting.