I don't see how that theory disregards LoS' setup. Gabriel Cronqvist becomes Dracula for whatever reason, a new Belmont emerges to take him down (obviously being oblivious to the fact that "The Dragon" also called himself Belmont at one point), and it could be like the classic games all over again.
Or they could just have Gabriel battle his son which may or may not be Alucard, and then his grandson, then his great-grandson, etc. It's too bad Cox already boxed himself in story-wise by making that epilogue.