Actually, I can count two. Doctor Hooves = Doctor Who (and Tardis), MY EYES!
Raven: It's Whooves, and the whole comic is a crossover of Doctor Who, not a ref.
Yes, it's Whooves, but he himself is a reference.
Raven: At first, but then became a character of the crossovers.
Indeed, but he can still be considered a reference to the Doctor, even if he has gotten his own reputation and backstory.
Raven: No, he got promoted from a reference to a character of a crossover.
Ok then.