I don't think that Mianaai is an AI. AFAIK, she is cloned. The clones meet at regular intervals and share their knowledge, which helps maintain a sense of a single individual. In some ways it's actually the reverse of how the AI's work in the book.
I generally think of Breq as female, but I had some real problems with Seivarden as she/he kept switching gender in my mind. It's actually an aspect of the book that I have come to enjoy. And it's quite a skillful achievement for it to be able to stand up to a reread. I'm already looking forward to reading it yet again later this year

u.