My thanks to everyone who voted! Dark Shadows (1991) received 4 votes in the poll; Dracula received 6 votes, once everything was tallied up on both the LJ poll, and the Dreamwidth poll. So when nominations open for Yuletide, it will definitely be Dracula for the third fandom.
I’m re-reading the novel right now, actually. I know for a fact that I should definitely nominate Jonathan Harker, and Mina Harker. I'm being attacked by prompts to ask for when it comes to Jonathan anyway. I might nominate Lucy Westenra for the third character. The fourth is either going to be Dracula or Van Helsing.
ETA: And so it's settled--the fourth character nomination for the Dracula novel will be Van Helsing, and I'll cross my fingers and hope others nominate the rest of the cast.