My guess, Hosh > Ono, Ao > Koto (but K looks good this basho!), Atami > Oshou --> Ao > Atami in playoff.
The biggest/closest/consequentialest match is Aonishiki vs Kotozakura. I don't think they've met previously without K being injured, so it could really go either way.
But yeah, like uh, wow, there are some permutations here, man.