In an interview given at the Comic-Con, Crews confirms another EX3 cast member (hopefully it's official enough for the movie bosses!). Although he sounds clueless and follows the interviewer's lead, he does not deny the addition of Jovovich to the EX3 cast. He also mentions that he has not seen the script, however expects to be in the movie himself but doesn't sound too sure.
In another interview, he further confirms Snipes & Chan, but again sounds uncertain of his own participation in the 3rd chapter. Chances are he's in it but I'm sure Sly has different plans for this third installment. Despite the initial plan for a trilogy, there is strong indication that if EX3 is successful there will be more sequels and Sly is setting the stage for more to come. Arnold has already confirmed that he'll be in all of them.