Some few observations: Everybody thought about Ray Haffner after we discovered that RJ probably was a Visualize member, and Brett Stiles may have some more connections with him.

When PJ was in the mall with Bertram, why the RJ friend (which pretended to be him), was there and with a gun? To protect his boss?

I'm not suggesting anyone, just bringing something many people thought. Who is RJ was decided since the first episode?

Would be cheating if he didnt decide since the begining who Rj is. Because leaving connections enough to make a way to show any of the 7 as the real Rj, would be a fake puzzle. If he reads blogs, he would avoid the most popular suspects.