I wonder...
Lorelei mentioned that PJ and RJ are a lot alike, that they could have been friends.  The only person with whom PJ seems to have a "friendly" relationship with is Stiles. 
Re-watch their scenes together, it's like a tit-for-tat conversation, back-and-forth witty comments. 
Stiles may not fit the clue profiles we've heard from Rosalind et al. , but as we've seen over the seasons, RJ is many.  That ability to bring so many into his circle, drink the perverbial kool-aid, and to have them do his bidding....