You have EK, possible only because of location(kind of weak for sound reasoning).
Lea, I mean come on, she makes hounds out of people on a regular bases AND makes them enjoy it.
I Personally think no theory dismisses BC but infact emphasizes their involvement.
My Personal theory: WK.
Mainly because He had his little fingers EVERYWHERE(lara inherited his influence and was able to drop a Navy Chopper in another country), He was calling up demons such as HWWB. He had to get that knowledge from somewhere, and we KNOW he has had contact with other wizards and such before we ever saw him.
Since BR, HWWB has not been located, though we know he's free.
Further Evidence:
Lara has information on top-level wizards at her finger-tips. Where does she get this information while the WC is at war with vamps?
Not to mention the information she had was NEW, such as Carlos' position.