As a trans woman myself, a part of me is just glad you even attempted including trans people at all. lol
An option of having each set of genitals for each body type, like male body with penis, male body with vagina, female body with penis, female body with vagina, would be really awesome, you don't even need any customization beyond that. (Koikatsu Party/Sunshine does have mods that make those all possible) I know that's a lot of extra work, and would take a good while to fully implement but it would be cool to include trans men and trans women in a porn game. (everybody faps, so including everyone would be nice to see. lol)