Hiei would appear at the wedding and then vanish quickly because URGH FEELINGS. But he'd end up getting them both some kick ass wedding present or something he got in Demon World after some tough searching somewhere. I'm sure Spirit World has beaches and stuff. As long as they don't go to Demon World, they'll be cool but they could spend part in Spirit and the later part in Human World. Best of both worlds?

NO NO NO I'LL JUST DELETE IT. IT'S FINE. *cry* Well it's mostly filler up top...you can just skip to the second half of it lol