Re: the Eastern European immegrant/vampire thing.
A couple years ago there was an article in the James Joyce Quarterly linking Leopold Bloom (Ulysses) with vampirism- using, of course, the old blood libel. I mention this because Stoker himself was a Dublin man.
Also, the vampire is closely tied symbolically in Stoker’s work (and others) with sickness and plague- which would have run rampant through immigrant quarters.
But I doubt that’s why he’s wearing it. It might actually be a joke. I believe it was Carl Lammele at Universal then…widely known, apparently, as a nice guy who would adopt you like his own (the rhyme about him went something like “Uncle Carl Lammele/has a very large family”) A lot of the studio heads were Jewish at the time, too…what better poke?