Um...It's a joke.
However, look at this fucking character and tell me that's a heterosexual with a straight face.
Sorry, I don't get the idea behind this. I could look at Lady D's appearance and trailer debut and make a number of inferences about her, but none of them would have anything to do with her sexuality. If anything, the only thing that would suggest something about her sexuality would be heterosexual, since in the Village trailer, she's seen sucking Ethan's wrist for blood, but that's not indicative of much sexuality-wise. Vampiric, yes, but as batshit insane as RE can be, it's always avoided actual supernatural elements. Yes, even Eveline is 'grounded' in science, despite being a ghost girl trope.
Also, cards on the table, I haven't played Village (yet), but I've never understood the fascination with Lady D, said fascination coming as soon as she was revealed in trailers. But under the inference of my own that there's some kind of 'queerness aspect' to her, then surely, Morpheus is a better candidate for that in the RE series? Because aside from that, it's not as if the RE series has lacked in female antagonists, not even female antagonists that are aristocratic, are super-strong, and look down on the plebs as being beneath them (see Alexia Ashford).
Dracula...Yes. I actually do realise that.
Like, you do know Dracula is incredibly homoerotic right? Like, countless books have been written on the weird amount of queer subtext and coding in Dracula, on Bram Stoker's weird relationship to (and anxieties about) sexuality which he channelled into his work, and how this carries over into subsequent depictions of vampires in media.
Alright, cards on the table again. I've read Dracula, and I'm well aware of the themes you described, but having read the book, I just don't see them. Don't worry, I'm not claiming that over a century's worth of literary analysis is somehow wrong, but while I have a dim view of the novel in general (you can see my comments on it on the book thread if you want), but I don't see much "queer subtext" there. Again, what examples of sexual interaction are there? Dracula bites two people in the book (Mina and Lucy, both females), while not bothering with Harker, and kills (not bites, kills) every (male) sailor on the Russian boat. We see his brides, who sort of have some kind of 'kink,' but they try to bite Harker, while also having some love-hate relationship with Dracula himself. Every incidence of vamprisim in the book, if you're framing it through sexuality, is heterosexual. Dracula bites females, the brides try to bite Harker. There's no incidents where it goes the same-way, so to speak.
As for subsequent depictions of vampires in media...sort of. We can probably agree that vampires in pop culture can trace their genesis back to the novel in some form or another, but what those vampires do, and even how they operate, are going to vary by setting. And even if you want to look solely at the sexuality aspect and "queer coding," then examples I'd actually cite (if at all) would be the Lahmian vampires in WFB (predominantly female vampires that almost only turn females), or the Styrian vampires in Castlevania. A series that, frankly, made Dracula a more complex character in two seasons than Stoker did in an entire book.
Again, I can accept Dracula's cultural influence, while generally disliking the book itself, even if I can admit that's probably a fringe position.