You've completely missed the point. This "leaker" is very clearly hinting at Geno. If Geno isn't #5, that means he would have to know about a post pass character 3 months ago, before they knew about Terry or #5. Keep in mind that 3 months ago, nobody had any clue extra DLC would even be a thing.
It doesn't matter if he got just a couple things right, he completely missed easily the most important mii costume of that batch, and mixed in some **** that shouldn't even be happening according to himself.
I understand exactly the only things that could have happened; he got ahold of a tiny little bit of legitimate information and decided to just mix random stuff in according to trends at the time, or he just completely made a guess. Goemon isn't even that difficult a guess, since Goemon is one of Konami's classic arcade franchises.