I'm largely working under the same assumptions that not too many newcomers is a half-truth, the ballot is being used, and Mii Costumes were a concession.
The roster officially has 80 characters (84 counting Mii Fighters and Pokémon Trainer as 6 characters instead of 2), which is a great number for marketing purposes. While 17 characters is the same number of newcomers added to the base game in Sm4sh, it's really 12.5 unique characters (Daisy, Chrom, Isabelle, and Dark Samus are echoes and Dixie is a Semi-Clone), which is lower than both Brawl and Sm4sh.
King K. Rool: I think it's safe to assume that K. Rool performed well in the ballot. Not just in the West like Ridley, but overall. Sakurai is definitely aware of the demand, seeing that K. Rool recieved a Mii Costume. I don't imagine that Sakurai couldn't come up with a moveset for him, as his problem with Ridley wasn't size, but conveying his vicious fighting style and being true to his character. It's definitely possible to make K. Rool true to his zany self. If we don't see K. Rool, then we'll see Dixie as a consolation of sorts.
Geno: Again, Geno likely performed decently in the ballot, moreso in the West. However, Geno's been a long time coming with his potential inclusion being a thing since Brawl. Sakurai likely already has a moveset prepared and only needed Square Enix's approval. He's already got them at the negotiations table, and he's already negotiated to use Geno as a mii costume, so I think next he's going to negotiate for Geno as a character.
Ashley: She's Japan's Ridley. Sakurai has commented on her popularity, acknowledging it with a Mii costume, and she'd be the "Little Mac" of this game. She balances out both Ridley and the Little Mac trend by being a predominantly Japanese pick. She'd bring a full mage moveset to the game, so she'd have a unique moveset too.
Bandana Waddle Dee: A moderately popular character overall who also has the perk of relevance in the Kirby series. A little bit of Sakubias could carry him as well. He fights with a Spear, which is also new to Smash Bros. in terms of movesets.
Lloyd/a Namco Rep: Lloyd is my bias, but I see us getting either Lloyd or Heihachi/a Tekken representative. Both are popular, having received Mii Costumes, represent prominent game series (Tales of being one of the "big three JRPGs" and Tekken being one of the big fighting games), and could bring new movesets to Smash (Lloyd with dual wielding swords and Heihachi with a Tekken based moveset). I think it comes down to two factors: who's more popular and who Sakurai can come up with a moveset for. Hell, we might get both at once, or (my guess) the other as DLC. If Lloyd is made into DLC, there's the possibility he becomes Yuri Lowell due to Tales of Vesperia's popularity and the upcoming definitive edition. However, looking back at what Sakurai said about Heihachi, I don't think we'll be seeing him in this game. When asked about Heihachi, Sakurai said "However, implementing Heihachi’s movement in Smash would be difficult." I think what's significant here is that he's not citing lack of a moveset, but difficulty of implementing the movement of Tekken, which is a 3D fighter. The 3D aspect is important to the series, and I don't think Sakurai and his team are going to be able to emulate to a point they'll be satisfied. Instead, Lloyd presents himself as a 2D fighter (no free run in Tales of Symphonia) with an already viable moveset (dual wielding swords) and louder fan demand than Heihachi. If we get another Namco rep, it's likely going to be Lloyd. We could also get Heihachi alongside Lloyd or as DLC though.
Simon Belmont: Not just due to Vergeben, but also because he's a popular third party pick. I think Simon Belmont would still be a popular character in fan speculation without Vergeben as he and his series are iconic. A whip moveset could also open up a lot of possibilities. I legitimately think that if Simon gets in Konami had something to do with it. There are a couple of leaks that state that Konami specifically requested Simon, or even held Snake hostage and forced Simon in for Sakurai and his team to use Snake, and knowing Konami nowadays it sounds plausible. Castlevania has also been seeing a recent push from Konami in the form of the Netflix series, which has a second season coming out this October. The show's been in development for 10 years, and was likely picking up steam behind the scenes when Sakurai approached Konami to use Snake. Dude's also iconic, and is really the last true classic third party we need in my opinion. Plus, dude also showed up in a fighting game with Snake and Bomberman, so I feel like we'll be seeing him in some form.
Chorus Men: A scrapped idea from Smash 4 (evidenced by Gematsu) that Sakurai can now add due to no technical limitations holding him back. A moveset is prepped, assets from Smash 4 development likely already exist (Smash Ultimate is built from Smash 4), and there's nothing stopping them this time.
Chibi-Robo: He's our WTF character, but he's also a Nintendo icon in his own right. His series has been around and kicking since the Gamecube Era, with him appearing on every console minus the Wii U in one form or another. In 2015 he also had relevance, with Chibi Robo Zip-Lash coming out then.
Dark Samus: An echo that's easy to make and promotes the upcoming Metroid Prime 4. Also adds some much needed Metroid representation.
Chrom: He's the perfect echo in my eyes. Sakurai has said he'd be too similar to Marth and Ike, he's made fun of for being too similar in a Palutena's guidance conversation, and Ike's moveset practically fits 1:1 on Chrom. And Sakurai gets to avoid Fire Emblem controversy as he takes little to no development time because he's an echo and he gets to please Fire Emblem fans who've been waiting for Chrom since the last game. Celica as a Robin echo is an honorable mention.
Isabelle: A popular character (she's practically the face of Animal Crossing) that's easy to add and appease fans. It's perfect.
Dixie Kong: A popular, relevant Donkey Kong character who was originally planned to be in Brawl. I imagine her being a semi-clone of Diddy Kong (or maybe an echo), which makes her easier to implement as a character.
Incineroar: I think he's the most likely Pokémon newcomer given that he could bring a unique fighting style to Smash, being that of a grappler/wrestler. That fighting style is classic, and I think Sakurai would want to represent that in Smash Bros. through Incineroar.
Erdrick: One of the leaks today I read really got to me when it said that the Japanese weren't as hyped about Smash 4 as Americans were with picks like Little Mac. I think that makes perfect sense. Characters like Little Mac and now Ridley cater primarily to American fans. Case in point: Little to no one played Ridley in the open tournament tonight compared to characters like Ike, Ness, and Inkling. I feel like this "Ultimate/Special" version of Smash Bros. is meant to cater to both western and eastern fans equally. Characters like Ridley and Geno are largely western picks, whereas characters like Ashley and Erdrick are largely eastern picks. Of course, there is overlap in terms of western/eastern appeal with all of these characters, but certain characters cater more towards certain demographics this time around. Plus, Sakurai might as well take all the Square Enix characters he can while he has them at the table, right?
