I think it is safe to assume that magical otherkin would not have a problem as they would be able to express themselves by becoming Animagi, but what would we call a magical person of unconventional gender?
I doubt they would be happy being called a witch or a wizard, as both terms presume a strict gender binary, so what term would they use?
Please note that this question is asked with tongue firmly in cheek, but I do wonder if any thought has been put into this type of question by either the fans or JK herself.