I honestly think we are getting 6 more newcomer and a few echoes. Smash Wii U did a very poor job handling many of the bigger franchises with only Mario receiving multiple newcomers and Pokémon receiving one, and I believe that Smash Ultimate will rectify that, putting more emphasis on the heavy hitters in a similar fashion to Brawl. Here’s what I mean, leading into what I believe will be our roster;
The Golden 4 (Will Get a Newcomer + Potential Echo + Returning Veterans)
Super Mario Bros - The series already has Daisy who is important for representing spin-offs and Mario’s first steps onto handheld consoles (excluding Game and Watch), so she was important to represent things like Mario Kart and Land. Mario will get an actual newcomer though in the form of Geno, who represents the large RPG side of Mario as he was the first character to come from Mario’s steps into that genre. Geno is also speculated due to Verge leaking a Square character.
The Legend of Zelda - The series will have two reps, one echo and one original. The echo will be Impa, who got a surge of popularity due to Hyrule Warriors, plus she is the only non-Triforce weirder to be reincarnated for multiple entries in the series, being a staple 4th wheel. She is also the last remaining Shiekah in most titles, which is an extremely important race in Zelda, so she would be an easy Shiek clone. Skull Kid will then be the original character. He is known to be popular as Sakurai has commented in the past, plus he’s extremely iconic in that anyone can look at Majora’s Mask and instantly say Zelda. He hasn’t been shown as an assist yet and has hints in the room similar to K Rool, so the chance is high.
Pokémon - I can easily see Pokémon just getting one character due to getting 3 veterans back already, but Inciniroar will probably be the gen 7 rep due to Verge’s leaks. An echo for a gen 3 Pokémon may also be possible due to the recent remakes that were released in time for the ballot. Inciniroar will most likely be the only new Pokémon though.
Kirby - Banadana Waddle Dee will be the new comer as he’s super popular in the Kirby community and Japan, and people have been requesting for a 4th Kirby rep for years. He is also the missing member of the modern Kirby crew, so filling that obvious omission would be nice. As for an echo, then Galacta Knight or Dark Meta Knight due to their reoccurring villain status in recent titles, plus they’re creations of the modern Kirby team, so Sakurai may want to commend the work they’ve done without him.
The Loved B Tiers (Returning Veterans and Echo Central, Newcomers are Rare)
Metroid - We already have the two main villains of the two separate Metroid series, so it’s done.
Star Fox - We got Wolf back, so no need for anymore characters since that would just lead to a Kirby situation where there are obvious omissions if we get Slippy and not Peppy.
Donkey Kong - While we already have K Rool, Dixie Kong as a Chrom style echo may be put in to fill the omission problem as we have 3/4 of the SNES Donkey Kong Protagonists/Antagonists. All other DK characters are practically extras, so just getting Dixie makes sense.
Fire Emblem - There will be no completely new characters. Chrom will be one of two echos though, as while a Chrom was the popular pick, The Black Knight will be the villain pick to fill all the big franchises with villains. He can be an easy Ike echo, and the Castle Seige Black Knight armor is gone, hinting at his inclusion.
Animal Crossing - The series is probably finished with Isabelle, but who knows, an echo may show up, even if it’s Tom Nook like the trailer felt like it was hinting at.
The New Series (Newcomer + Echo)
Splatoon - While Inklings are probably good enough, and Octoling echo seems likely as that would bring in a Splatoon antagonist and they are very popular with the Splatoon fandom.
Golden Sun - The only series that’s super popular and has gone pretty much unacknowledged by Sakurai, especially in Wii U. I expect Isaac to appear as the 5th character after the golden 4 have their fun, as he is very popular and has been hinted at with that photo. Matthew may also be an echo of Isaac to add an extra bonus for Golden Sun fans
3rd Party
Castlevania - Already revealed with Simon as a newcomer and Richter as an echo
Microsoft? - They will get one franchise in the base roster, most likely are the three amigos; Halo, Banjo, and Minecraft. I’m guessing a new character plus an echo for the franchise, but since Verge said Minecraft, it’ll probably be Steve with an Alex echo, sorry.
Basically we will be getting Geno, Skull Kid, Inciniroar, Bandana Waddle Dee, Isaac, and a Microsoft rep as characters in the next few months as my prediction.