As would Jack/Aziraphale, though I can't guarantee he'd be nice to Az. "Ok, I don't care what you say, unless you are a Scotsman on a windy day, tartan is NOT stylish." Actually, Jack would probably think Az was gay, too. And that would be a riot.
I don't see Jack and River getting along at all.
Crowley/Az is obvious. Crowley/Amelia would be interesting and Crowley/River... we should probably not entertain for the benefit of everyone.