P.DelSlayer said:The only reason Yveltal wouldn't have a new type is that it is clearly a Dark/Flying or Fighting/Flying.
iirc Mewtwo's new forme was mentioned as being its 'Awakened forme' on pokemon.jp, but I'm not really sure on that.
It's type is obviously Psychic, because original Mewtwo was Psychic, but a dual type Psychic/Fairy just doesn't seem right. My guesses on Mewtwo's new forme are: it will officially be called Awakened Forme Mewtwo, and will be a pure Psychic type, with stat improvements/readjustments.
I agree with you completely on revelations from X/Y, with a huge *fairy type?* announcement in May, and then monthly news.
The person who leaked the B/W dex was called Hirobyte, but Pokexperto may have done it as well (I don't actually know if they're the same person)
Pokexperto did as well. They are not the same person but they work together. Here is an article from Pokexperto explaining himself and Hirobyte as well as the speculation of a new type:
http://www.pokexperto.net/foros/index.php?topic=38576.0