I actually find it fairly hard not to believe this stuff. The stuff Melkor said matches up well with the translated interview (assuming the translator isn't just fucking with everyone), which is directly from the designers. Also, unless he was planning on closing his site soon anyway, he's going to lose a lot of traffic if he's wrong (though I'm sure the spike he's probably got at the moment could cancel it out a bit).
The main reason why I'm still a little skeptical, though, is just because of how stupid and unrealistic some of them seem. The big one in my mind is the starters final evolution's typing, Grass, Water, and Fire/Fighting seems like it was just designed with the intent of pissing everyone off. Beyond that, there's a three stage moustached shih tzu apparently, along with a line starting with a guy with a wooden plank that grows a clown nose. Kurumiru has the same head post-cocoon. Basurao has two forms but doesn't evolve. Hihidaruma apparently can turn half psychic. Also, the Normal/Psychic sounds just weird (she has a hat?). Lastly, #641, 642, and 645 are apparently a trio, with Zekrom and Reshiram at 643 and 644, and the dragon/ice at 646, which just doesn't make any sense to me at all.
Right now, I'm hoping that if they're real, he just saw the sprites, so he can't make out most of the details, and is just guessing on the types. Which wouldn't surprise me too much.