Nonbinary?
While not the most traditional or mainstream view of nonbinary identities, one of the main characters is a transfem nonbinary butch lesbian. Another is questioning their identity and coming out, and there are multiple other nonbinary characters. Also, body horror as an exploration of gender is pretty trans IMO. And of course both authors are enby

what does this thing mean to you?
My favourite character in this book is a Mixed, traumatised nonbinary transfem butch lesbian with violent urges and a desperate need to hide her pain. Getting to show this character and how worthy of love she is despite everything done to her, and everything she does to others, was hugely important to me. Also, I live for the complexities of identities, especially gender-related dual identities in a contemporary setting.