This is my theory:
I think that RJ isn't someone from the list.
I mean,we are all thinking that RJ is someone from list and Bruno knows that if he puts someone from the list,half of people will be disapointed with that choise.I think that after all this seasons that we watched,Bruno doesn't wants to disapoint any of us.I think that he will choose a safer possiblity.I think that he will choose someone from CBI or someone that we would never suspect(My first suspect is CBI Ron,but maybe I'm wrong),and everyone will be suprised with that choise(No one will be disapointed).
But maybe I am wrong.Bruno knows the best ending of this series and i think that in the end it will be a big suprise who RJ is.

So thats my theory.Comment bellow and let me know what do you think. :)