Here are basically my final thoughts on leaks. I think leaks in general are really boring compared to discussion of actually playing the game, but if we're going to be so leak crazy, I have some thoughts about how things probably are. Two points really.
For one, "box theory" as people like to call it is almost assuredly correct. It just makes too much sense; the idea of a professional design for a special edition or whatever box being custom made and manufactured just to be shown briefly in one trailer and then something fundamentally different is used for actual sale only a few months later is insane and a basic contradiction of how businesses work. We also were given this "drought" of reveals with Sakurai telling us that they went overboard with reveals and needed to slow it down (and then actually doing that, showing basically nothing for an entire month) which combines nicely with the statement from the very beginning of there not being too many more newcomers. If you took this "Grinch leak" at face value, none of it would make sense as we'd have a number of newcomers comparable to other Smash titles and the previous reveal rate could have been sustained directly to launch. When something doesn't make sense like that, something has to be wrong somewhere...
For two, leaks have been really, really all over the place, and even someone like Vergeben who at this point obviously has real connections is citing things that would contradict the box theory (he talks about both Incineroar and another SE character which is numerically too much). It seems likely Nintendo has tried to intentionally obfuscate (probably making fake leaks themselves and such just to make it harder to figure things out), but the extent to which we really don't know anything is kinda absurd. This close to release we almost inevitably should have a much clearer idea of what's going on; a project this big involving this many people with this much public demand for information not working itself into that kind of situation is crazy itself if you think about it. Somewhere, there's something we just don't know that is really important to how things are.
Here's my theory. I think work is very deep underway for a lot of the DLC in this game. I think Ken and Incineroar are the last two characters, but at least some of the other stuff we've heard about in various leaks is real and is just DLC and no one leaking has any clue what's actually in the game and what's DLC. I'm totally unconvinced by this "Grinch leak", but even if it turns out to be real, every one of those characters could just be DLC. Smash 4 DLC was insanely profitable for Nintendo so I think it's pretty safe as a bet we're going to have a much bigger focus on DLC in this game versus 4. This also allows a lot of the "leaked" characters to not even be as concrete as we like to think since they aren't even a part of the main game's dev cycle so we could easily be getting leaks of what is basically early concept work that will never go anywhere at several points. I would surmise that, if this is the case, it will always be impossible to really learn much more from this point forward; every leak will inevitably be an insanely incomplete picture, and we're always going to be hearing about a ton more stuff than we could ever realistically expect to happen even from credible sources.