We were asked how trans vampires work in this setting.
The answer is: very broadly “however the individual player wants, provided it’s not upsetting anyone, and kindred society definitely doesn’t care about someone’s cis/trans status, as it has far better things to be prejudiced about, like who slighted whose grandsire in a casual conversation 300 years ago”. (Please see our E&D policy, if you are at all confused about this.)
Vampire biology is weird magic, and we see no reason to be prescriptive or even consistent about it. What happens for one vampire may not be true for others.
So, if one player wants to declare that their character was taking hormones when embraced, and their body has now locked at that state, and no longer needs them, fine. If another player would like to declare that their character still needs hormones, but they happen to be the one thing other than blood their character can consume, also fine. If someone else just wants to declare that their character’s gender presentation changed in their sleep one night, also fine. Vampire bodies are inherently magic, and do things human bodies cannot.
(NB: the above applies to trans players who might wish to play trans characters. While we wouldn’t say “never” for a bunch of reasons, we would be very cautious about allowing a cis player to play a trans character.)
Players of either gender are welcome to cross-play, of course, and this is not connected with a character’s trans* status.