Y'know, the protagonist of the very second Oz book (The Marvellous Land of Oz) was a boy who turned out, at the very end of the novel, to have been a girl all along, who had been enchanted to be a boy. And he became Ozma, the Princess of Oz.
Also, in the original novel, the Wizard himself appeared to the Tin Woodsman (I think it was the Tin Woodsman, it might have been the Scarecrow) as a lovely lady. She might have been an illusion of some sort, or it might have been the Wizard (whom in later novels we learn does indeed have the capacity to cast magical spells) in polymorphed form, or an ally or servant who spoke on the Wizard's behalf.
The point here is that I think that L. Frank Baum might have been delighted with reading this thread. And with following the story that will come out of it.
If the Tin Woodsman's Lady was a servant of the Wizard's, that gives us another female part. Has the Wizard himself been spoken for yet? If so, there was a particular winged monkey who flew off with Dorothy. Maybe he didn't take her directly to the Wicked Witch of the West, having some personal interest in his captive first?