here's a list of what I think, logically, should get Fairy: (excluding what we've already had confirmed)
-Clefairy/Clefable. No need to explain.
-Snubull/Granbull - same as Clefairy, they're classified as the Fairy Pokemon and could easy be Fairy type
-Togepi/Togetic/Togekiss - the whole kindness thing seems Fairylike; their appearances can easy bee seen as Fairy
-Mawile - I wouldn't have expected this if WPM's source hadn't said, but I'm taking the source 100% now. *
-Misdreavus/Mismagius - not only does Ghost/Fairy with Levitate give it 3 excellent immunities that most other Pokemon would give up most of their BST for, it fits perfectly with their design origins.
-Milotic - the whole calm thing, plus beauty, seems Fairy.
-Cresselia - the good dream thing fits it, plus it's always seen fighting Darkrai and the 2 seem to be, for the most part, balanced; ingame this obviously doesn't happen because Psychic is ineffective to Dark. A Psychic/Fairy against a Dark type would give balance. It's also the one legendary that I think should be retyped, that is, if any are.
the 'maybe, could go either way' list:
-Audino
-Happiny/Chansey/Blissey
-Skitty/Delcatty
-Bellossom
-Politoed
-Volbeat/Illumise.
I'm really hoping that not all the cutesy pinkums are retyped, pink=/=fairy.
* could WPM's source have more retyped Fairies other than Mawile/the confirmed ones? It may not, but still, could be worth looking at