[spoiler]Dark Pit confirmed, apparently the guys who got the game early though suck major balls and can't beat him.[/spoiler]
So far in total, I'll try to sum up what I've seen up to this point:
[spoiler]Three streamers, all Japanese assumedly and not that great at the game.
CHALLENGERS SO FAR (in order): Ness, Falco, Dark Pit, Duck Hunt Dog, Game & Watch, Ganondorf, Dr. Mario, Wario, Lucina (why was an announced character a challenger? Ah well.), Jigglypuff, Bowser Jr., ROB
LEAKED/KNOWN CHALLENGERS LEFT: NONE LEFT, SORRYCOOL STAGES NOTICED: SNES F-Zero track, Magicant with nods to the Mother games in general
OH [parasitic bomb] BOSSES: Master Hand and Crazy Hand, obviously, but they've got new moves, and are deadlier than ever because even on easy difficulties their attacks come out
fast. Crazy Hand only appears on a harder difficulty it seems, but there's actually something i'll note in a separate spoiler.
NOTABLE CLASSIC MODE CHANGES: The Kid Icarus: Uprising-style Difficulty Slider you get after selecting your character is definitely more scaleable than before, and things get pretty damn difficult at 9.0. The route system works in that your character moves on their own, but you can slow them down and pick between 2-3 different paths depending on where you are in the map (up until the end of the mode for the final boss, anyway). Trophies and items are occasionally scattered on the routes, and although you see pre-emptive series logos, what the match type and enemies may be are still up to guess. Which route you choose seems to determine what boss you get, possibly along with the difficulty slider too. Rather than choosing your stocks, you get 2 stock per stage - which means they replenish to two, but still means two deaths and that's it on any stage whatsoever. Getting Game Overs seems to cost you overall coins at the end as well as automatically toning the difficulty down by 0.5.
NOTABLE CHALLENGER FACTORS: Dark Pit is a ridiculous clone, I can't even tell what's different from what I've seen of him besides using a staff for his Final Smash and different weapons for some of the specials without any changed animations. Duck Hunt Dog is fanservice galore, he's various Zapper games rolled up into one reference to the point that one of his moves is literally leading a series of Zapper shots meant to be the player trying to shoot him. He even does
the laugh as his intro. Dr. Mario has the Down-B Tornado back. Ganondorf's still a swordless buff(ier?) Falcon. Wario seems to have gotten better animations, although I haven't seen his attacks to judge them.[/spoiler]
I'm not even watching these streams anymore, the players keep suiciding and dying. Hamayama in particular just spams Specials like nobody's business and gets his ass wrecked for it.
Extra Special Spoiler breaking down something I saw and you may not want to spoil for yourself (sorry for those who saw what I mentioned before):
[spoiler]
Master CoreOne of the streamers, gema_yue, went through Classic Mode on difficulty 5.0 with Marth. Earlier they got the encounter with Mii Swordsman. I only saw the Marth run. Right as you go up to the path towards the Master Hand final battle, certain conditions apparently let you take a 'darker' route up towards a fight with Master and Crazy Hands. Big life bar, but it's counted separately so you can kill them individually. However, once one of the Hands were defeated, Crazy Hand teleports out and Master Hand spazzed out before he transformed into a mass of black energy almost resembling the shadow bugs from Brawl, and it's only called 'Master Core'.
It has three phases, the first two either dependent on your character or randomized; in this case, a swarm of swords throwing projectiles and themselves around, followed by a fight with a pitch-black Marth larger than the player. The more damage you do to them, their HP counter blocked by darkness, the more desperate they get but also the weaker they get, metaphorically speaking - the dark Marth got smaller and more normal-sized the more it got hit. Once you break down its forms, the music fades out and it transforms into what's basically an idle Small Ball core that gets a normal hit percentage, doesn't fight back, and keeps going back to the center of the arena until you manage to do enough damage to smash it off the stage.
Presumably, higher difficulties might change this, add more phases, or potentially even have different bosses. No one knows yet. Apparently the mass of swords of the first form were instead a giant, distorted dog for the Mii on the first run. And.. Uhh.. Apparently, he went extra freaky on the only 9.0 run to reach him so far, a Kirby run...
We're talking 'turning into a vaguely humanoid mass of darkness that lifts the Final Destination stage itself and [tornado fang]ing headbutts you' freaky. Even worse, the higher the difficulty, the more phases he gets, so it seems on hard enough difficulties Master Core goes through all three phases before cloning you. And you have to do this all on 2 lives, plus the Hands fight before it. Worse yet, with only 2 stocks per stage and the 0.5 difficult decrease per game over, you [tornado fang] up enough and you don't get a chance at all the forms in one battle. No one's going to know the result of a full perfect 9.0 run for a bit longer.[/spoiler]