I keep hearing and seeing this... its on DS as well.
People seem to think it is Charlie VS Freddie VS Lisa VS Marcus.
Also I think if Lisa is up along with Charlie and Freddie we Freddie fans need to be careful, Charlie and Lisa fans will unite together to vote out Freddie, so we would need to choose only 1 member of Lisa's Team to vote out, if you get what I mean, if Freddie fans half the vote to Lisa and Charlie it could result in Freddie being evicted!
Thats how Nikki went, all of the fans of the other Hms saw her as a threat and all voted to evict her.