I'll make some guesses about who's who by generating ideas which solely binds me but maybe some people might agree...

Red John: Complicated. How? He seems to be a master-mind of crime as well as the cover-ups by highly smart moves that nobody could catch him so far. He is also a great manipulator/mentor who controls many people by means of persuasion? hypnosis? threat? blackmail? whatever you call it, people die for him intentionally. We see this pattern in some terrorist organizations but even in those, people may kill themselves under drugs mostly. However, RJ disciples reflect more of a sane pattern which makes us think that they are not drugged but they are somehow influenced. So, I am asking myself: How come such a crime-artist / well-organized brain can get so aggressive and stupid enough to kill people who just insult him? You don't expect such a temper from a man like this. It seems like an instant and not well-thought behavior which is almost amateur act to me. I can't just combine these 2 qualities (mastermind / jumperboy) together in one man. This is why I think there are 2 characters making the concept Red John a whole. There is one orchestrator and one killer (besides the accomplices). Perhaps the mastermind and psycho killer are having argumentations on each other's acts to eliminate contradictions. However, this only happens when there are serious contradictions. Otherwise, there's a master plan and they both pursue a unique goal by their own ways. For instance; maybe the mastermind got mad at the psycho about why he killed Jane's daughter where it was totally sufficient to kill his wife and let the girl wake up in a blood bath. And the psycho retorted that the girl got awake during her mother's killing so it was inevitable to silence her too. This kind of stuff I mean.

STILES: He has a bound with RJ as they were sharing a common context before things get ugly between them. They are both dangerous and equals by many aspects. So, they still have an understanding. RJ never intrudes Stiles' area except for some little touches (using Visualize resources from time to time), and in return, Stiles doesn't reveal who RJ is yet feels confident enough to share some little info with his rivals (Jane for instance). He actually told Jane that he knows everything about RJ but there is a certain limit to what he can reveal. Seeing this, I think it can be safe to say that Stiles has a history and an ultimate understanding/a silent agreement with RJ. Both being equally dangerous can be seen from the fact that Stiles is still alive despite he gave Jane an advantage at some point by letting him know where Frye was. Was it an order given by RJ? I don't think so. Will they be coming to a point where they have to fight? Maybe. Maybe the Visualize coup was a warning by RJ to Stiles telling him that he has to behave (against his revelation of Frye's location). See? No direct action but cold war between the two. Hostility and mutual respect is also there. And Stiles wouldn't show this courtesy to a simple psycho killer I believe. There must be a higher path.

I don't know if I should nominate certain characters who's the mastermind and who's the psycho killer. To be honest, I am guessing that the killer is Partridge but I haven't figured out who the mastermind is. Having Brett as the killer will make sense to most people which will also come with a great disappointment for the show but the show will pull it together with the reality that it's not over yet and that there's a bigger picture. That's where the excitement will arise again. This is what I think will happen. Enjoy it fellas...