Well many predictions from Pokebeach are actually true, so fairy type seems very plausible. Also the poison type needs a boost. AND Sylveon looks like a fairy type. But that's a whole other discussion.
Crap, I was one of those people who laughed at anyone who said sylveon would be fairy, and one of those people who laughed at anyone who even said fairy would exist. Still, fairy type speculation has been around for how long? It'd be a pretty big coincidence if something completely fan-made made it in.