You both make valid points imo. What I will say is that I don't believe anything is accidental in this world. Inevitably symbols themselves will mean different things for different people.
Imo, the harpy was picked because they wanted a creature that could fly so the gamer wouldn't know they were fighting Dracula until he materialised. However, In context a bat would be more appropriate..
This is where I believe Morning star has a valid point, because I've played Haunted Castle, at the start of the game Dracula kidnaps the protagonist's bride. Hence, there's no element of surprise anymore, the gamer already knows who they're going to fight. If anything this just informs me that the creators did their research, I don't believe the harpy was chosen by chance. I'd be more inclined to believe they reused the harpy sprite (in this scenario) because they were too cheap to create another sprite. (Lucifer is said to have been beautiful, androgynous even. So maybe boobs aren't going that astray) It's the same reason why in the original SFII, both Ryu and Ken's sprites are in essence the same, everything is about cost.
Morning Star, speaking of context one thing I will say is when it come to Bram Stoker's Dracula, never watch the film, always read the book. The film is more a love story, and although good for its time I don't believe personally that it's a great adaptation of the classic.