I am with Krautboy on this one. Most likely Whitney and Dawn will go one after the other.

Meanwhile, on Redemption Island, a castaway makes a bold threat to his former tribemates during the duel challenge, and two castaways are sent home

Regarding the above clue. I am more apt to think the one that makes the bold threat to his former tribemates is one of the losers. We know that his former tribemates are Savaii, but it most be someone that was tribemates with them all as well. Therefore, I am thinking that Jim will be beaten and he'll make a bold threat to the remaining players regarding who he will vote for to win before he burns his buff and heads off to the jury.....something like, if you don't vote Cochran out immediately, you will not get my vote to win the million. This sounds like something Jim would indeed do.

He'll make a statement that will motivate them to cut Cochran loose....at least that's what I think...