Very cool tool! Great idea and well executed!
I have two suggestions, in case you are still working on this:
1, it might be nice to have a pronunciation guide to the pronouns. I could definitely use the guidance! XD
2, it feels a bit odd to have Dracula referred to as “a man” even when using a non-masc pronoun. I’m guessing this is probably part of the original text, but replacing it even with “human” could make things much smoother reading.
In all cases, thanks for making this!