Responses
Jimin didn't explain himself why is he dressing as a girl, so, I think it's ok calling him as male.
I always considered Jimin a guy who enjoyed roleplaying as a female by crossdressing in his freetime - we'll see if they're a transwoman or just a crossdresser (=・ω・=) I'll try to refer them as "they" until we get a definite answer. I hadn't really considered Jimin being trans.
I know I might be a horrible person for saying this but that ghost or illusion or whatever of Hyunwoo's girlfriend can to to hell. I don't even know anymore what's the point of having her there, seriously. She's not doing anything useful and now she's got Hyunwoo thinking about suicide. So, Jimin to the rescue or death. And is Jimin trans? Should I call Jimin with he or she pronouns? I'm still a bit confused about that. Jimin says they want to live as a woman but maybe there's aa history or something behind there. Oh well, I guess they'll explain it at some point.