The vampire hunter could be Richter, but last time I checked Richter doesn't have buckles on his pants (both the dxc version & sotn art of him). Also he doesn't have rist buckles, but the outfit still resembles Richter's. The art looks like Kojima's.
I'm trying to examine his identity by reading the character select screen, but I could only make out a few words. Vampire Hunter, and.. something "the Holy Whip". As for the girl, I could only make out "Lady". Maybe someone could raise the resolution so we could get some answers!
It's also a possibility that this game has no real story, and we'll just be controlling a nameless Belmont & slay Dracula as usual. But I hope not.