I was also wondering this with a character that is genetically male (XY) that had Complete Androgen Insensitivity Syndrome, and so developed with a phenotypically female body.  Would their fae self echo their biological sex, the sex they developed as, or the gender the character identifies as? What if these things were in conflict?  When magic to change how you look is easily accessible as a level 1 treasure or level 1 art (metamorphosis) does it change the impact of the disparity?  Is it banal to use magic to make your fae self to look like your autumn self?  I was tooling around with that idea for this game, but decided it was a bit too navel gazing.   I still think it is a great character concept though.