So far;

- "Tyger Tyger" is organization. In this organization probably no body knows RJ identity.

- I don't think RJ is founder. Joined afterward.

- I can say that Partridge is a member of this organization. And The Red John or organization decided to kill him.

- Also Bertram , Smith and McAllister are definetly part of this organization. But obviously none of them RJ.

- Now we know that Bob Kirkland has a twin brother. And he is working for RJ.  Probably that twin brother "Micheal" Kirkland killed Lennon guy at the hospital in Season 5. That's why Bob Kirkland asking Haibach " Do you recognize me , have you seen me before ? "

So two suspect left. Haffner and Stiles.

I'm not sure but for me best candidate is Haffner.