just a crazy thought based on Stiles opening line of his discussion with Pj at Ecuador Embassy .
Stiles; Dear Boy
Pj; I am not your boy

Could it be that B.Stiles is the biological father of both, Pj and Rj!

Things to be noted.
*Rj seems to know everything about the 7 suspects, even their fear. This explains why we see most of 'em are good whistlers, others fear of heights. He gathered all of their fears, then he fed these information to Sophie .

*Stiles big laugh when Pj said; someone in this room is Rj, indicates that; none of 'em is Rj. And please remember his words "I know so much more than you "Pj" or Red John Could ever imagine"