Transgender pronouns are difficult to adapt to using, and not even sure how standardized or well known they are. Only have ever heard of ze for he/she, and hir for him/her, but don't know what is used for his/hers. Hir also sounds like the word, here, which is messy. It's a bad choice of sound. Using pronoun preferences is usually easy enough, but would probably just always refer to a person by their name if they preferred transgender pronouns.