Ok, now that all the discussion about leaks and theories died, let's make some predictions for the last 5 characters (DLC):
1: Rhythm Heaven character (now that the Grinch has finally been proven fake, I think that Karate Joe is more likely than the Chorus Kids)
2: Steve (Minecraft)
3: Final Fantasy Character (Probably Sephiroth)
4: Gen 8 Pokèmon
5: Geno
I'm almost sure about Steve and FF character, because Vergeben was right.
Something in favor of the FF character: the DLCs bring in the game some more music, and this could be an explanation for the fact that FF still has only 2 tracks (with the DLC they will add more FF music, and I think Sephiroth is the best character for this, think about One Winged Angel).
Chance: 90% (both Steve and FF character)
I'm pretty confident about a Gen 8 Pokèmon. Gen 7 has been around for a while now, and they'll probably show the new gen soon enough.
Chance 75%
About Geno, since Piranha Plant is now a character, I think that all the arguments like "he's not important, he comes from an old spin-off" are invalid, and Geno is like a legendary character for Smash, I can totally see him being added at the end. But that's just my guess.
Though, he's a spirit... this may play against him.
Chance 50%
I'm unsure about Rhythm Heaven... it has been rumored and requested a lot, it makes sense, but I'm still not sure.
Chance 30%
---------
I think that Dixie Kong is now unlikely, because she's a spirit. I think that characters such as her and Ganon are important and should be added to the roster as soon as possible, though it seems that everything plays against them this time.
I'm not sure if spirits count as deconfirmations, but until it's proven otherwise, I think they count.
Chance 20% (Dixie only)
Despite the fact that Piranha Plant opened the doors for generic enemies to join the roster, I still think that Bandana Waddle Dee is unlikely: I think it's a toad-like situation, and for some reason Sakurai don't want to add those type of characters in the game. Not to mention that Piranha pretty much took all the stuff that would have made Bandana unique (regular enemy to fighter, small body with disjointed hitbox, long range attacks, "spear-copter") and added even more to the mix (stretched attack, blowing the spike ball, poisonous breath, etc).
And Waddle Dee (regular) is a spirit, if this even counts.
Chance 10%
Magolor is a spirit. I don't know if spirits count as deconfirmations.
Chance ??% (depends on if spirits deconfirm characters or not)
Isaac came back as an assist trophy again, sadly. Everything can happen, but still.
Chance 2%
Banjo... I don't think he's really that hype of a character outside the core Smash community. He was in Sonic & Sega All Stars Racing and almost nobody cared. He has a lot of fans, but for some reasons I think he's unlikely, all things considered (including copyrights, but in case of Steve that wouldn't be a big issue)... but who knows.
Chance 8%
Sora: that's kinda possible, but there's still Disney into the mess causing problems (probably). But that's another possible newcomer, it's just that I see him as less likely than the ones I listed above.
Chance 25%
Maybe there is some other character that I forgot, or some other unexpected ones, this is all but a complete list.
(I hope for Adeleine & Ribbon but the chances are low sadly).
