I really don't understand why people get so angry about rumors. Even when they're false, it's fun to see what people are thinking. If nothing else, Mr. XY put a lot of good thought into his list.
No he didn't. He put a lot of thought into it, yes. But I wouldn't call it "good thought" by any stretch of the imagination.
That's up for debate. His proposed typings for Yveltal and Xerneas hit each other with STAB super-effectively, Froakie's final form being pure Water is consistent with the current starter typing patterns, his Skarmory pre-evolution being Normal/Flying is consistent with Skarmory's Pokedex entries, etc.
I don't think there's any chance of XY being real, but the fact that we can't disprove it based on the Pokemon he suggests does mean that he put some "good" thought into it.