Gotta agree, "Gay" is not precise term to talk about someone who has their sexes changed, because technically speaking you are not gay if you like opposite gender after your gender changed, i actually simplifies the term gay for "someone who attracted to their former gender" in gender bender manga/anime.
And yeah looking at the list, i can add more of "Guy turned into a girl and fall in love with guy (usually the their first male friend)" because how mainstream it is, but not with the one where MC is attracted to their former opposite gender.
準備段階からニッチな題材とは言われつつもあえてそれを主軸に、この20年描いてきた作品の延長にある「少年漫画」を描いてみたいと思いました。
It's pretty clear from context that the "niche subject" he means is the gender-bending. Based on that statement, I'm confident Matsuri's female form will be relevant for the duration of the manga, and possibly become more focused on, though I wouldn't assume it'll be so in the same way.Although it is said to be a niche subject from the preparatory stage, I wanted to draw "Shonen Manga", which is an extension of the work I have drawn for the last 20 years, with that as the main axis.