First off, I don't know who Red John is.
But I strongly suspect that there will be a twist. He is probably not someone we currently suspect. Or if he is, there will be a twist of another sort - perhaps a shock revelation about who in CBI is aiding him.
Some other thoughts:
1. Lorelei Martins is still alive. Red John faked her death (twin, plastic surgery, whatever) and the video of her naming the suspects was made AFTER Jane had completed the list.
2. Van Pelt has become involved with Bret Stiles. Recall the scene when he is in custody and begins speaking to her and she actually begins to look interested? My guess is that she got involved with his group and has (maybe) been passing information to him.
3. Bret Stiles is not Red John, but he knows who he is - that is clear from earlier episodes. Red John may have some "dirt" on Stiles or an involvement in the cult.
4. Rigsby and VanPelt are leaving the show this season - apparently there will be a wedding in episide three (maybe them?). Red John may go after them - or one of them anyway.
5. Bob Kirkland is hunting Red John for National Security reasons, or for personal reasons - but not just as "a cop" doing his job. Perhaps, like Jane, Red John killed someone he loved. Or maybe Red John is some sort of risk to someone in government. Kirkland has stolen copies of Jane's files ... but we don't know what he knows.
6. Summer will be killed by Red John - or abducted by him to lead Cho into a trap.
7. JJ LaRoche is not Red John but Red John knows things about him which give him leverage should he need it.
Anyway - that's my tuppence worth ... enjoy the show!