I've always loved this headcanon, also I have an outfit exactly like that lmao.
I think that might just be a rumor, the Sonic News Network specifically states that Tails was suppose to be a boy from the get-go, although that would be cool if it was true.
it's tails in a dress, by cate wurtz. "a second image has hit the thread" :3
Trans Tails best Tails!
I've always loved this headcanon, also I have an outfit exactly like that lmao.