Umineko: Maid-sama's Female Yasu theory

Now, before I say my piece, let me state one thing - the story of Umineko is set in a time where gender equality was definitely not as strong as it is now.
Therefore, when I state that one of my first ideas as to why Yasu is female is based around the fact that they dress in female clothing, arguing that they may have been a male child, dressed in a female servant's clothing won't really work.

Let me explain. If Yasu had been male, then Kumasawa and Genji would not have dressed her in female clothing. Why? Because the main reason they have Yasu working as a servant is so that they can keep her/him safe, but also hidden from Yasu's father/grandfather, Kinzo. If they had wanted to hide their gender, they would have dressed Yasu in male clothing, as the main concern they harbour for Yasu is that, much like her/his mother Beatrice before them, Kinzo may develop incestuous feelings for the child (Yasu's mother Beatrice was the child of Kinzo Ushiromiya, and Beatrice Castiglioni. After Beatrice Cast. died, Kinzo grew insane with grief, and, believing his daughter to be a reincarnation of his dead lover, she became the object of his sexual desires, and so Yasu/Lion was born.)

Another theory to this, which is probably one of the most popular theories leading to believe that Yasu is in fact female, is that all persona's she/he has created are female, with the only exception being Kanon. Though, this isn't exactly a very strong theory, given that you could argue that if Yasu was a boy, whilst also being forced to dress as a female, he would identify more as a girl, and would want to create personas which are female.

A stronger theory, and one which I believe rather strongly in, is Shannon. Another of Yasu's personas, Shannon was created to be the perfect servant, and Yasu's friend. Yasu would see Shannon as being a glorified version of his/herself, so it would make sense that, if she is in fact a bigger, better version of Yasu, that she would be female. Again, I realise you could also argue the 'identifying as female' theory here, but I doubt this.

I am, of course open to both sides of the argument. Though I myself have come to see Lion/Yasu as female, I know that there are very valid points when it comes to the male theory, also. The existence that is Yasu/Lion greatly fascinations me, and I enjoy spending time looking him/her up online (mainly the Yasu existence, as that is the one which is surrounded by the most mystery), though Lion interests me too.