I always felt the chainsaw Frankenstein (or as I like to call him Frankensaw) was an obvious Evil Dead reference.
and while there have been many movie Dracula's I've always thought that the design used by Kojima very stroingly resembled the one seen at the beginning of Blacula.
Funny thing since Coller (the scrapped Frankenstein character in CV64) was supposed to have a gun as well, thus furthering the Evil Dead reference. Also Dracula's design in SoTN seems to be based off the book depiction of Dracula.
Shifting the topic back to fighting game references, Albus' flame kick thingy is an obvious
ripoff homage to Fei Long's flame kick thingy. It's even got invincibility frames, making it a reversal of sorts (although iirc, Albus' version works more like the Shoryuken in SSFIIT and some other Street Fighter games, where you're invulnerable until you land, at which point you're defenseless due to recovery frames.) It's a very obvious
ripoff reference, but I'm kind of fond of it (love thsoe invincibility frames) and I'm surprised no one mentioned it.