Van Pelt look too naive especially in season 5 when Stiles played with her mind like she is a toddler.
But maybe all that is a mask and act she is playing,
I don't have any clues or explanations but i believe that Jane is playing some games for a long time and he don't believe in that list. No matter what Bruno Heller said.

And also those clues that we know about RJ about physical look, age, even gender can all be lies.
Also it is clear by know he is not just some serial killer. He created a cult,like I said before he is on some kind of mission in his own mind.
We don't know his motives and we can only guess.