Have you considered

a barn owl ring bearer? For the couple with no adorable nieces or nephews and maybe a Harry Potter thing?

Ring-ring

"Hi, Dale? I guess you're not there, but I just wanted to see if you were available this weekend. Some friends of mine are getting married...the wedding's circus themed, and, well, their clown backed out. So they need a clown to marry them. If you're around, give me a call."

-my coworker on the phone this morning

My dream wedding dress