The problem with all of what you said is the fact that it doesn't disprove the alternative. Your points are rationals for why they could be true, but it does not prove enough concrete evidence that he isn't just making it up. Again, the alternative is he made a lucky guess and got the others right. I'm not going to go into specifics on what you said because the same answer comes up: It also could be just as likely that he is making it all up. Again, you have to throw out the alternative all together. You can't rationalize it. You have to outright disprove it.
On #1, you are using the Texas Sharpshooter fallicy. He guessed them! He must know something. Again, there is nothing to prove that. He didn't get them in order either because Rosalina came next which he never said.
On #3, he said a broad category and not a specific character. This is confirmation bias at work here because you see it as "He knew Greninja," when in fact he gave a very broad category and someone was picked from that category. He was not very specific, and likely for that reason I stated: if he made it all up and didn't want to be caught, you'd expose yourself to a lot of risk by saying a specific Pokemon which has numerous potential characters.
I'm not sure what you want him to do to prove that he isn't making it up then. He's not just going to show us the email or give us the guys information. Many people have emailed him as well such as
CAW Evolution who I'm sure he actually trusted. From what I've seen, he's given CAW more than enough information or even the other guys email/message to show that it's not Sal himself making this up. (CAW Evolution is an older leaker, and a guy who's known to have insider information, also leaked the entire roster of Ultimate MvC3). I'm 99% sure that CAW even knows what position the guys source is working in, and won't say too much so that he won't get in trouble. Sal himself is skeptical of the leak, and isn't even passing it off as true yet. He always says to not fully believe it or take it as fact until further evidence is provided. Why would a fake leaker do that, especially one that's in charge of an entire website. If this is fake, would he really want to tarnish his website's reputation like that? However, Sal trust's his source, no matter how skeptical he is.
On #1, Once again, I said that
of the newcomers that were shown at E3, the ones that were shown were revealed in perfect order in correlation with his post, and were even in between the characters that were not revealed in his post. Even then, they were grouped together as well. In his original post, he listed Animal Crossing Guy, MegaMan, and WFT. That is the order they were revealed and I am positive that it's not a coincidence they just happened to be in perfect order, and even In between the newcomers that were not revealed. That is not luck, and I'm not sure how far you're willing to say that everything is "luck". It's certainly possible, but all odds are pointing to the fact that it was not luck.
On #3, once again, it does not matter if he said a broad category or not. By the laws of our language, he got it right. No ifs, what's, or because. He was correct and that's the end of it. You can call me biased if you want. Yes, it's extremely skeptical and we have every right to be in regards to it, but he was still correct and that's the end of it. This does not skewer him as much as you are making it out to be. And listen, out of that generation,
not that many pokemon even had the potential to be chosen; that is in the link I showed you. Even if you got the most broad of pokemon, only a few would have ever had the chance to be playable. Of the 70 pokemon, the only important pokemon that could even qualify to be used proportionally are the starters, the Mega Pokemon (I won't be picky as the other form of the Mega Pokemon weren't from Kalos, but there), and honestly that's about it. It's not as broad as you think.Both GameFreak and Sakurai will chose a pokemon that's popular, whether it's in the game or upcoming movies. (FYI, Greninja is going to star in the next movie). Not that many XY pokemon were even popular enough to ever even be considered.