Hoping for both of then to become mosters. If they switch roles, it kinda defeats/muddles the comparison the author is making that monster/otherness/queerness is actually not bad. I think the author is ultimately saying that being a monster/queer is neither evil or good, it just is a different experience from human/heteronormative. So if they both become monsters, then it's just who they were meant to be. The medium lady is kinda that gay family member who has internalized homophobia.
I hate that woman from the start, if yoshiki want to be a monster or stay with one she can't interfere, "normality" for him is only a prison with only sadness
So yes i hope too in this ending
I think this finish or with both of them in the other side or that yoshiki becoming a monster and Hikaru human