I'm certainly not gonna be correct on this but here's my predictions anyways
Erdrick: For right now Erdrick seems to be the most likely Square rep cause of a multitude of things. Every leaker as far as I know are in unison about Erdrick being in (Yes I'm doubting Verge but I'm only taking his word with a few grains of salt, not fully disbelieving him), DQ's Legacy, DQ's Very healthy relationship with Nintendo and Square likely wanting to push DQ to the West are just a sample of things Erdrick has going for him. I think Erdrick is in or at least I think he is as of right now.
Geno: I know and recognize that this is the Stupidest thing in the world to predict, but I think there might be two SE reps as Square loves money and if they put two Reps in as DLC that would enhance the profits made from Smash at the very least. Erdrick could be for y'know his Legacy and shilling and Geno could be for the fans who want him. SMRPG References have been everywhere in the past few years, The Mallow V Geno tweet, the Happy 22nd anniversary tweet, The Trivia question, Megasmilax, PP's Classic mode image, even a reference in Crafted World it's Strange I mean we could pass it off as fan service and apologizing for not getting Geno in smash but that only works if the References in question were only in Smash, not Crafted world. It sounds conspiratorial I know but I have this gut feeling we're getting both or, at the very least Geno will get in as a bonus character.
Banjo: Say what you want about how unlikely Banjo is and how likely Steve is in comparison but I disagree, Banjo is being low-key leaked by some people so while they may not be true the more leakers the higher the chance of happening as the more leakers saying Banjo is in the more likely that at least one of them are right. I can't really explain why I feel like Banjo is in cause if I say that Xbox live could be a plus for Banjo the same could be said for Steve, I just think Banjo is in.
Sans: I feel like there's a good chance of an Indie rep happening cause in this day and age Indies are huge, they make up a good chunk of games that come out so I feel like there might be an Indie rep because of it. Shovel Knight is gone, if Spirits are to Deconfirm Shantae would be gone and I don't think Steve is actually happening so who better to represent Indie games that the Skeleton boy himself, Sans. Sans is popular and recognizable all around the world so being unrecognizable to the Mainstream isn't a problem, Sans would be unique (not necessarily a point for Sans but it's nice), Sans already has his game and his Spinoff game on the Switch, Sans would just fit and I think he would get in.