Ah no problem, the sensual vs sensuous thing is very confusing, even native English speakers get it wrong all the time so very easy mistake!
(also warning for anyone reading this who hasn't read the book or played the game yet: spoilers will be mentioned)
I definitely agree with you, from what I've read...LeFanu is definitely not a great writer. Not even slightly. And he was sort of passed off as a sort of sensationlist genre writer even for his time. I definitely think he's far more interesting to see how he has pioneered and influenced a lot of his contemporaries rather than for his actual text in and of itself.
So I subscribe more to the second of your takes on Baron Vordenburg. I think he's important, but also...yeah, very poorly written and definitely a deus ex machina (when I first read Carmilla, I was legitimately confused if I misremembered the General as a Baron because the Baron was so out of nowhere at the end.) I feel he runs counter to your interpretation of being open minded to that which cannot be easily explained because, well, he literally does that. Comes out of nowhere at the very end to give an (overly clean) explanation to everything as well as a convenient (male) expert to explain away anything there was left to wonder about Carmilla. If there's any wonder or mystery to be had in the text of Carmilla, Vordenburg kills all of it in an almost Holmes-ian way, except worse. And, if you were to tell me that LeFanu needed an extra 10-20 pages to fill out before sending the manuscript to the publisher so he threw in that last chapter, I'd believe you. However, I do think that final chapter (though poorly written...though...the whole of Carmilla inherently textually is pretty spare under analysis) is still important to because it does give the final explanation of Carmilla...or Mircalla... (because LeFanu has laughable taste in anagram names...) and gives finality to the events. I also think Vordenburg is extra-textually important because he is, ultimately, a contemporary of famed the Van Helsing. I don't think Stoker's Van Helsing would exist had LeFanu not written Vordenburg beforehand (that said...Stoker's vampire hunter probably deserves his greater fame).
Ultimately though, I don't mean the baron is important because he's a crucial piece to the whole text as a mega important character, I don't...think much anything in LeFanu's Carmilla is written in a way where anything deserves that honor. The bigger concern for me was that I saw a bunch of comments talking about how they'd never read Carmilla before, and it concerned me that many people could walk away having played this game thinking they've read the full text when an entire chapter was omitted. I think if people knew that this was an editted adaptation that was not 100% the real text, then I honestly wouldn't have a problem at all. I think this project was beautifully put together with a very interesting interpretation. It stands very well as an example of recontextualizing and reconstructing a literary (can I call Carmilla "literary"...?) piece of work under analysis. And the fact you put this up for free is insanely amazing, I was actually a little sad I couldn't give you at least a donation (I don't know if maybe the fact it leans so heavily on an existing work made it so that you couldn't monetize this project). And I totally understand not wanting to delay the project and devote more dev-time for the last chapter, again especially because this game is free. My biggest concern really is transparency that this is more of an adaptation or heavily editted edition to the players.
All that said, I'm hoping you continue to expand on Visual Gothic, namely some of Swedenborg's work since you seem so passionate about it!
P.S: Did you ever find it...odd? How similar? Swedenborg and Vordenburg's names are? LeFanu is definitely the type of writer who would make low effort references so.........
P.P.S: For clarity's sake, I don't think Carmilla is so bad it's not worth engaging in. I don't want anyone to feel like I'm trashing on Carmilla as an unreadable piece of work. I think it's a lot of fun and a great exercise to see how it influenced Bram Stoker's Dracula and later contemporaries, and some of the research on its conception is also a lot of fun too. But, a great writer, LeFanu is not haha.