My money is on Laura not graduating from burning candles at both ends unless she gets a hail Mary from Trevor's mom to help her sister. But Linda would be my second choice and Trevor, my third, although I only think that last will happen if Matt ditches him. As a wild card, I might see Alex dropping out because he's finally forced to deal with Grandma himself, can't, and rage-quits to 'show' her.
Jon, on the other hand, will probably graduate and then have no idea what to do with his degree. That seems to be how he rolls. Then again, he seems to have turned a corner, no longer mooning over Candi, so maybe his drive will pick up, too. he wouldn't be the first person to suddenly stumble upon what he really wants to do in an odd place (as far as his original aspirations go) on campus.
Candi will likely hook up with Chris, then dump him, because even though Chris has his financial head on straight, I suspect being romantically faithful is not in him or will at least be a great struggle, and Candi's already been burned. Candi seems to have a talent for gravitating towards bad romantic choices. At least we have an idea what will happen to her: graduate, and then be kind of at sea.