Doesn't quite work, since the Creature is no different than having Dracula dipping around Romania centuries earlier, as well. Mentioning Quincy and the events of the novel is pretty specific, like if a Castlevania game mentioned the murder of Victor Frnakenstein's wife. Do the games bring up minor characters from the Frankenstein novel and tie them into the games, like with Dracula?
Look, if one of the games had, as its plot, "Dracula worked as a CLown in Munich," then that would be canon to the game, no matter how silly it sounded. Just because they halfassed the novel connection doesn't mean it's not there.