This roster works off of some assumptions:
- When the roster was being decided, the Ballot was taken into account and played a major role in character decisions
- Mii Costumes are evidence of Ballot success
- Echoes are being used to pad out the roster. Some Echoes were added later into development, or with knowledge of upcoming games.
- Sakurai's statement of "don't expect too many newcomers" is another half-truth, in that we're getting less unique newcomers, but a similar number including Echoes.
All that being said, here are my predictions:
Unique newcomers:
K. Rool: I know the argument for a character performing well in the Ballot is hogwash, but I seriously think K. Rool did well in the Ballot. Additionally, he could bring something unique to Smash Bros. as the heaviest character in the game. This is a Smash Bros. focused on fan-service, and K. Rool is a well requested character, at least to the point that he was acknowledged with a Mii Costume.
Ashley: She's Japan's Ridley. We got Ridley, they get Ashley. It's balanced, as all things should be. She also brings something unique to the table as a mage/spellcaster.
Geno: A former idea of Sakurai's and an overall well-requested character (was acknowledged as a Mii Costume). Now that Cloud/Final Fantasy is out of the way for Square Enix representation, Geno is the next in line. He's an angel-doll thing, and can morph his arms into cannons and use timed attacks for more damage.
Bandana Dee: A well requested character who has been prominent in recent years (especially around 2015 when the roster was decided) and uses a spear, a weapon unrepresented in Smash Bros.
Simon Belmont: An iconic third party representing the second half of the "Metroidvania" genre, and the last member of the Captain N Crew. I also think Konami pushed for his inclusion for Sakurai to get access to Snake (a part of the "risks" associated with the project). He could use a whip-based moveset alongside the items from Castlevania.
Leon Kennedy:
BluePikmin11
brought up some good points about Leon Kennedy. I believe that part of "Ultimate" or "Special" is a culmination of gaming as a whole (Sakurai has confirmed that Smash is a celebration of gaming at this point, and I think this game is going to up the ante of that claim), and each third party pick reflects this. Leon Kennedy represents the entire horror genre through Resident Evil, the father of the horror genre, and is the character most associated with Nintendo in the series. Capcom is on board with Nintendo (they let Ridley murk Megaman in his reveal trailer. That's trust right there) this time, and after Mega Man and Street Fighter I think we'll see either Resident Evil or Monster Hunter. I'm betting on Resident Evil due to the iconic nature of the series and it's role in gaming history.
Elma: Not necessarily as popular as the other picks, but she has relevancy at the time of the roster being decided, Nintendo pushing for her series, has Sakurai supporting her, and she represents the Wii U era of Nintendo.
Lloyd Irving: We are seriously sleeping on Lloyd. He's been a popular-enough pick from Smash 4 speculation up until now, and was even acknowledged with a Mii costume.
This reddit post makes some good points about Lloyd's potential inclusion.
Chorus Men: Again, Sakurai is revisiting former ideas, and the Chorus Men are one of those. Also, if Smash Ultimate is being built from Smash 4, then it's possible that the unused assets for the Chorus Men are being put to use for this game.
Chibi-Robo: Another character we're sleeping on. Chibi-Robo was relevant in 2015 with his new game Chibi Robo: Zip Lash releasing at the time. He's been a somewhat prominent series from the Gamecube to Switch era, and seems to have performed well enough in the ballot if
this is any sort of indicator (it likely isn't, but it's something). He could definitely bring something to the roster, and is also the "WTF" pick (not necessarily because he is somewhat popular, but he fits the bill
Lip: The "retro" pick for this roster. Despite most "retro" picks being niche, Lip is actually quite popular both here and overseas (I'll again refer you to
BluePikmin11
because he can explain it better than I will) and could have a moveset based off of the Panel de Pon series alongside her magical powers.
Echoes:
Dark Samus: I almost didn't include her in this roster, but I think with Metroid Prime 4 being in the works she would be added so that the game can be promoted. If she doesn't appear in the base roster, she'll likely be DLC of some sort to promote the game.
Chrom: The case for Chrom as an echo writes itself. He's a popular character (Mii costume) initially planned for Smash 4 (revisited idea) who was cut because he would be too similar to Marth and Ike.
He was even told he'd be too similar to Ike in a Palutena's Guidance conversation.
Dixie Kong: Diddy Kong lost his attacks involving his tail. Coincidence? I think not! Dixie Kong is a popular character from a series that is long overdue for more characters. Her recent relevance (at the time of the roster being decided) in Donkey Kong Tropical Freeze also helps her.
Isabelle: Isabelle is a popular character who has been a prominent member of her series since her debut. She's similar enough to Villager that she would be easy to include and her inclusion would please a lot of people.
Ocotlings: With the recent release of the Octoling Expansion, I believe that Octolings are going to be a late inclusion meant to represent the now prominent Splatoon series and the recent Octoling Expansion.