Ultimate is clearly drawing heavily on popularity: they mentioned it in regards to Ridley, Simon supposedly did well on the Ballot, and there's not really any other reason to add Daisy outside of her popularity. With that in mind I'd predict something like this:
- Simon Belmont
- Elma
- K. Rool
- Bandana Dee
- Banjo
Other names I'd keep my eye on: Ashley, Captain Toad, Paper Mario, and Geno.
Simon was leaked. Elma has the Skell-esque figure Sakurai got. K. Rool did extremely well on nearly every Ballot poll I've seen + he was acknowledged with the gold-bellied Mii Costume. Bandana Dee is another highly popular and unique choice. Banjo is on here just because Vergeben said we'd get a Minecraft stage and/or assist and Banjo makes the most sense as a Microsoft newcomer since he's popular and has ties to Nintendo.
For echoes I could see some combination of Isabelle, Impa, Shadow, and Dixie Kong. Shadow is on there because I don't think his AT has been spotted which is kind of suspicious, especially since he's a highly requested character. Although all of these characters definitely could/should be unique, the whole "echo fighters" branding seems like a sneaky way to add more highly requested characters as clones with less backlash. It makes even more sense since there won't be as many newcomers this time around, so Sakurai is going to pad the roster somehow. No Octoling because I don't think they're popular enough for this game.
I'm not predicting a new Pokemon because there's a billion and one Pokemon in this game so I'm not sure if Sakurai would prioritize a new one. I'm also not expecting a retro rep because Takamaru is an AT and I doubt Sakurai would add a retro in a game with less newcomers than usual.
Since we're getting less newcomers, I expect us to get a lot of DLC fighters, especially since Nintendo has been doing a lot more post-launch support these days. I would think we'd get 5 of them, but the only ones I would be somewhat "confident" in predicting would be Rex & Pyra and Spring Man. Outside of that I'd mainly expect other popular and unique characters who barely missed the cut, even if they were assists in the base game. Just pull an Alfonso for them and disable the assist if they're in the match.