Pretty random thought - Technically most of Touhou youkai girls can be considered trans
I was thinking about how the 2hu girls would react to trans people (result - probably mostly neutral or positive except Reimu), but if you think about it, canonically humans were convinced that all youkai are cute girls and because youkai are spirits they became ones through that, despite original myths clearly stating a lot of youkai kinds to be male in most of the stories
Originally it more of a projecting real world craze with femine humanizations of mythology on Touhou world because it is how Gensokyo works, making outside world’s fantasies a reality…
Well, it is still very fitting for Touhou, you can say realistic trans don’t really exist in Gensokyo because it is fantasy where fully changing sex is pretty much possible, maybe even by a lot of different means depending on if you can ask Yukari to revert borders of cis genders or hold it in-between, or instead will rely on magical spells or potions, or will (secretly from Reimu) become youkai and change perception of yourself