I love this fuckin ship ngl lmao, It'd make sense. I mean, Mr.Hippo always talks about Orville within his stories and not much about his other friends which I doubt they care. Orville and Mr.Hippo relationship does seem canon about being extremely close friends.
I can see it happening, however I doubt it would as they seem only to be friends. They also don't seem to have any souls in them or built to murder kids ( We do not talk about them killing William Afton in UCN as he deserves it )!
So rating time?
7/10