I still believe that it is possible. Chris said that no one could vote Courtney off and I assume that it's going to continue. If Courtney didn't have the power to sue the show, then she wouldn't have a purpose for returning. She has come back for revenge and since she's not so much as a strong competetor (no offense to Courtney fans), the only way that she could get her revenge on everybody is that if she files against the show to increase her chances of winning. If she didn't have a safety net, she could get voted off early and then there would be no purpose.
Justin could very well continue his role as the antagonist, although where we last left off, he seemed to have lost his charm then.
Over the last few episodes, Justin has only specialized himself into manipulating other players. He has had no real strategy into competing in additon, Lindsay and Beth have grown to see through his act. The only factor that makes Justin seem like a threat is his charm and model good looks, but since everyone has come to realize that it was just a mere, temporary attraction distraction, it thus makes it difficult for Justin to survive. Courtney, on the other hand not only has come prepared with shielding, but also has maintained her original motive in place. I think and in the words of the collective on the board: Courtney would do anything to win. She has pulled acts of trickery, has stolen a hot air balloon, and in addition, can hold a grudge for an extended period of time. So as long as she has the lawsuit, me thinks she's invincible this season, compared to Justin who can only get things off of his good looks, since it's beginning to ware down for most of the competetors, Justin's chances for winning are gradually slimming. I assume that Courtney may outlast him and become the new villian. This show is compelling for it's uncanny unpredictability, so it's anybody's game. Although, between Courtney and Justin, it's debatable to determine who will outlast the other.