It all depends on where in the multiverse the crossover happens, if it happens on earth, all my supernatural beings would be disguised granted they'd still look a bit Bunny Eared Lawyer
I could see many crack pairings.
My Anti-villain Protagonist
character from the shounen-like would most likely find my Uke
MC from the other world annoying as hell, and My uke most likely find my Villain Protagonist cold and heartless. Though in the same vein both are the protagonist in a Coming of Age
story, the difference being the genre and their angst levels my sweet and kind uke has only cried once despite being whisked away to a fantasy land without warning and being told he may never return to earth, while my "villain" has cried in almost every chapter.
My mentor character and my Seme character might get along, both are older than they look, both are snappy dressers, both have a bad habit of coming off creepy, and both are hurting from a lost relationship with another male that just keeps haunting them. (The seme's is sexual, the mentors was a friendship.) Both losses where Face Turn Heel .
Though the Seme being part angel part demon and my Mentor being highly spiritual might impact their chances of being friends. Plus my mentor despite being straight seems to come on strongly to other guys My MC in the shounen has lampshaded this and accused him of being a pedo. Twice.
so my Seme
(who is bi) might see that as an invitation.
My two females characters
from the shounen world would love my uke character, mainly because they are all Otaku, plus he was raised in a soba noodle shop and they both love soba.
My vampire from the romance story may or may not get along with my MC from the shounen both are sarcastic jerks with vampiric abilities but the romance one is the Friendly Neighborhood Vampire
while the other is a low morals energy vampire and a human which he hates. Yes, him and the uke have BTS .
It would actually be a rather fun if not wacky crossover if it were to happen. I wonder what happens when deconstructed shounen meets fluffy romance?