So, I've been laying in bed, and thinking about who I think legitimately think we could see as newcomers. I've tried to set aside bias, and be as logical as I can. I've thought of "the rules" and criteria that are seemingly applied to newcomers.
Disclaimer: I am not saying ALL or ANY of these characters will make it in. I am just saying I would not be surprised if they did.
Normally the amount of newcomers range between 12-22 (15+7 DLC). Brawl had the most newcomers (pre-DLC) with 18 newcomers. That being said, the newcomer count normally always goes up. I've chose 17 potential newcomers and 7 DLC characters I could see coming.
Before I begin, however, I have to address cuts. There are always 5-6 cuts (Technically, Lucas was brought back so there were truly only 5 cuts.) Since this pattern seems pretty persistent, I will be applying here. Here is a list potential characters I could see getting cut.
The characters I could see being cut are: Cloud, Ryu, Mewtwo, Roy, Lucas, Lucina, Dark Pit, Dr. Mario*, Corrin, Greninja, Mii Fighters.
(From most likely to least likely, but still possible) Between 5-6 of the following are probably on the chopping block. I put an * next to Dr. Mario's name because I believe Mario's moveset will see modifications to align more with his Odyssey presence, and that keeping Dr. Mario will retain his original playstyle for people who prefer it.
Now, here is the list of newcomers I see having strong chances: (In no particular order.)
1. Inkling. (confirmed) (Boy/Girl variants)
2. Spring Man = Ribbon Girl. (Spring Man with Ribbon Girl alts. They are the poster children for ARMS. A new IP that debuted on Switch. They play similarly, and given a few "liberties" here and there, they could be alts of one another.) Think how Robin can not learn Nosferatu in game, but knows it in Smash.
3. A second ARMS character. Hear me out. I know ARMS is not as big as Splatoon is, HOWEVER, it offers a lot of diversity in its characters and arms. I feel the most likely candidates would be Min Min, Twintelle, or Ninjara. And yes, the character would be a semi-clone. SEMI-clone.
4. Takamaru or Balloon Fighter. We always get a retro rep, and I feel these two have the best shot of making the roster. In the case of Takamaru, he's been in almost ever Smash game since Melee. His only hold back has been not being recognized in the West. However, he made it in WiiU/3DS as an assist trophy, and I think he could get the "Little Mac treatment". As for Balloon Fighter, I just feel he is the next possible choice if Takamaru doesn't get in. He was popular back in his day, had his own stage in 3DS, and would be an interesting addition since he'd probably fight with balloons.
5. NOT A NEWCOMER, but a returning vet that would take up a roster spot. Ice Climbers. They are loved. They were missed. Sakurai wanted them in. Now, there's nothing holding them back.
6. Isabelle. She's become the second face of the ever growing franchise of Animal Crossing. Sorry, Tom Nook. I see her as most people would. A clumsy fighting character that would use other aspects of Animal Crossing that the Villager doesn't. She could be unique, but if she were to fall under the semi-clone category, I believe she'd hardly be one. Think Lucas or Luigi.
7. Hades or Medusa. "We need more villains!" Well, here you go. Personally, I prefer Hades over Medusa since he is the true antagonist of the franchise, but Medusa has been in more games. I think Hades has better moveset potential, but Medusa would represent a villainous rep AND female rep. With Kid Icarus being reborn by Sakurai, and a hopeful future due to the games success, I could see one of them making the cut. I'd be fine with either, I just prefer Hades.
8. Rex & Pyra. Xenoblade Chronicles 2 was pushed extremely hard by Nintendo. From what I can gather it was a success, and I could definitely see the two fighting as a pair. Possibly have Mythra an alt skin for Pyra. There is unique moveset potential.
9. Dixie Kong or Cranky Kong. Both would be wonderful unique additions to the Smash and DK franchise. I just can't decide which.
10. Paper Mario. It's the next logical choose for a Mario rep. I'm sorry to all the Toad, Waluigi, and Daisy supporters out there. Paper Mario would by no means be a clone. There are tons of things to pull from to create a moveset for him. I feel Odyssey will get it's representation in a slightly revamped Mario moveset. "Three Marios? That's ridiculous!" Yeah, but they'd be Mario in name alone. While one would be a semi-clone if left in his own slot (Dr. Mario), Paper Mario would be completely unique from both. We had 3 Foxes technically in Brawl, and 3 Marths in WiiU/3DS, they just had different names.
11. Impa. It's time Zelda got a newcomer, and one off characters like Skull Kid, Ghirahim, and Midna have missed their flight. Don't get me wrong, I'd love to have Midna or Urbosa, but I just don't see it happening. Hyrule Warriors has had 3 releases. 3. That's incredible. Impa has been a reoccuring character in Zelda for years, albeit in different forms, but I could see Hyrule Warriors Impa making the cut.
12. Mimikyu, Decidueye, or Incineroar. Mimikyu was heavily marketed in Sun and Moon. It's the 2nd most popular Pokemon from Alola. Unique typing. Incredible moveset potential. Decidueye could complete the fan perpetuated "Starter Type Trio Triangle". Unique Moveset potential, and could somewhat be a "Pokken" rep. Also, Decidueye was the most popular starter final for Sun and Moon. Incineroar could bring a wrestling gimmick to Smash, and we've all seen the leaked images. Ash is set to have an Incineroar at some point, and we all know in our heart of hearts the anime has some bearing on who makes the cut. Same could be said for Mimikyu in regards to anime presence.
13. Fire Emblem Switch rep. We all know it's coming.
14. Labo Bot. We get a WTF character added into every Smash. This one will be no different, and I believe the Labo Bot would be a perfect fit. Using Nintendo Labo aspects in battle.
15. Wonder Red.
16. Bandana Waddle Dee. I was iffy about this one, but after some research, he is the most deserved potential newcomer for Kirby.
17. Hero, Monster Hunter, or Rabbid. A 3rd Party hype character. Hero is from Dragon Quest, an extremely popular game in Japan. Monster Hunter, is from well...Monster Hunter, an extremely popular game in Japan. As for the Rabbids, the are the least likely of the 3, but after the frankly surprising success of Mario + Rabbids, I wouldn't be surprised if they made it in. I'd much much MUCH rather have Hero or Monster Hunter though.
I'm not even going to being contemplating DLC until the game comes out. The only one I have a good feeling about is a Gen VIII Pokemon rep. Cloud (if cut), Ryu (if cut), and Wolf (due to fan demand.)
So, what do you guys think. I'm sorry my descriptions are kind of messy, and that I didn't put some for others. I'm drifting in and out of sleep. XD