I wonder how, if it ever would, how Persona would handle non-human identity in its setting.
Persona has had a bunch of explicitly non-human Persona users - ie. jungian shadows, a dog, a few robots - but non-humanness as an identity could be interesting in its universe exploring the myths given life from the collective unconscious.
Broader thoughts on "Identity" and Persona
It feels to me like there's kinda two overarching perspectives on what constitutes "identity".
One is that identity is the image of your self. It's how you want to project yourself to the world, be it a sort of personal "brand" or as a desired physical vessel. Whatever other details involved depends on the person.
The other idea of identity is more about function and interaction. What your role is in society and your greater goals in life. This perspective I think is what Persona leans towards, and is probably reflective of Japanese work culture and gender roles. (It's also why I think The Discourse gets thrown at Persona, because people misunderstand its actual intention.)
... to be fair, maybe all the Persona-users are non-human and species-fluid anyway. "I am thou, thou art I", after all.
But still, it's because Persona is more interested in exploring how people interact and their goals and roles in life, that I suspect identity as a personal meaning and "self-definition" isn't actually something it's likely to focus on. If one could create a story about the "function" behind being non-human, as a role in human society, then that's something it could possibly explore.