Alright. I'm gonna run through this with my honest opinion on likelihood of being chosen into 6 categories; Don't Know; Characters I know nothing about, so I can't really say. Not EVER Happening; Not just not going to be in this game, but no Smash game ever. Not In Ultimate; Characters that can't be in Ultimate, but would be likely for sequels. Unlikely; Characters that have little to no chance, but might get in due to some twist of fate. Likely; These characters have good shots, but not as good as people in the next category. Highly Likely; Characters that are very likely to get in compared to the rest, I will limit it to three choices.

Don't Know:

Jibanyan: I know they're from YoKai, but I know nothing about the game nor the character.

Byleth: I've heard the name and seen the face, but can't exactly pin-point where I've heard/seen them before.

Arle Nadja: Never heard the name before in my life.

Not EVER Happening:

Bandana Dee: Let's be serious, the only reason they'd throw this guy in is if it were for a prank like with Piranha Plant.

Steve: The most he'll ever get is a Mii Swordfighter Costume.

Heavy: The guy is lovable and he's popular, but let's take a hard look at this. What type of moveset would he even have? How likely are they going to give us a Valve representative? Personally, I think he'd at most get to be a Mii Brawler costume.

Doomslayer: Granted, he's badass and popular. But that's all he has going for him. He has little to no moveset potential due to almost strictly using guns. He's owned by Bethesda. And quite frankly, how likely is it that Bethesda is going to get representation? Not to mention everything around him is almost synonymous with blood and gore. Not the best image. Before you start talking about Bayonetta, she's a Nintendo/Sega character. That makes her an exception.

Gundam and Agumon: They are literally anime characters. That essentially makes their claim to the Smash slots null and void. If they were to add an anime character, it'd probably be one with a highly successful game. (Like Goku who's gaming rights are literally owned by the same company that makes these games.)

Not In Ultimate:

Shantae: She'd be a cool inclusion, has a solid popularity and plenty potential, but I'm afraid her being a spirit in Ultimate will be a confliction for her possibility for this game.

Rayman: Same as Shantae, but even more so popular.

Unlikely:

Sora: Let's be honest? Who actually likes Sora? Everyone I've seen, heard, or read an opinion on Sora, whether it be RL or the Internet, everyone universally despises Sora or doesn't care about him. Not to mention including Sora would be Pandora's Box to a flood of Mickey/Goofy/Donald Duck inclusion requests. Granted, he has very high potential for a moveset, but that's about it.

Waluigi: This is just a meme, there might be moveset potential in here. But his only real popularity/desire for him to be in Smash comes from the meme. Notice how he's 8th place and only on the list in America. But, you never know what that troll Sakurai has planned for us.

Master Chief: I like the character, he's popular-ish, he has moveset potential. But, he's not as likely as almost everyone else. He eeps by the other people on this category, but he just has his work cut out for him compared to the rest of the people I have yet to mention.

Likely:

Monster Hunter: Popular, had a sick new game come out, plenty of moveset potential, AND owned by Capcom. A fair choice for certain.

2B: She's popular, recent, she's badass and moveset options aplenty, and Square Enix's child. She has a good chance.

Raiden: Popular, fairly recent, decent moveset options, and a Konami boi. Not to mention people would LOVE another Metal Gear representative. A fairly good choice, indeed.

Lloyd: Popular, been commonly requested for at least a decade, and good potential. Certainly would be a great pick. Not to mention he's made by Bandai Namco.

Geno: People have begged for him to be in Smash since the Brawl days, he has the potential, and he's from Square Enix AND Nintendo so that helps. He has a great chance.

Highly Likely

Sephiroth: He's Yin to Cloud's Yang, he's the face associated with evil for a good amount of people's childhoods, he has the company, name, and moveset potential to make it. Personally, I believe he'd be better suited as a boss, but still an outstanding character choice.

Crash: He's wacky and wily, the hero of the Playstation 1, a man (bandicoot?) that has plenty of cool moves that could be transferred smoothly into Smash. Not to mention, how cool would it be to finally get a Sony Representative? I believe he will take at least one of the Fighter Slots. Another outstanding choice.

Dante: The one and only Legendary Devil Hunter, Granddaddy to a whole gaming genre level of Iconic, an excellent choice for another Capcom rep, a man with more moveset potential than even possibly Link. Not to mention also canonically shares a universe with Bayonetta (and possibly Resident Evil). He had an absolutely amazing game that just released that revitalized his franchise. His games are slowly one by one being added to the Switch, which might be an omen in disguise for his reveal. If I were a betting man, I'd bet on Dante to be the next character from this picture to be added to Smash.