You seem awfully angry about this.
Not angry as much as I am just baffled that people are still falling for these.
Photoshopping some text onto a picture isn't quite the same as what this guy has done (if it's fake), there are brand new character renders on here and even in game screenshots. I'm not saying we should all just believe it's authentic or anything, chances are it is just a really elaborate troll, but I think some people are writing it off a bit too quickly. Like others have said, this is exactly what happened with Brawl.
Mii Fighter isn't there because the customisation mode is off (he did show screenshots that show the customisation options for them). Dark Pitt was hinted at in a previous trailer and considering Lucina is a separate character, there's no reason to think he wouldn't be as well. Duck Hunt is exactly the type of "huh??" character they like throwing into these games and Bowser Jr was considerably more popular a couple of years ago when this game would have been being designed.
The only questionable thing I see is the positioning of the characters. Yoshi is considered to be part of his own franchise, so it doesn't make sense for him to be inbetween Rosalina and Bowser, especially with Bowser Jr sitting after him. And if they're throwing the clones on the bottom row, why aren't Ganondorf, Toon Link and Falco with them?