I have absolutely no clue at this point--my powers of speculation are failing me.
If all the characters Verge said are what's left: One final Direct, with Incineroar, Ken, and the SE rep. If these are the characters, I'm betting on no more new stages. We delve into the single player mode (not called Spirits), we have a section on new modes, trophies, and Pokemon/items/assists, where a Creeper assist pops up. And--that's all I can think of.
My dream final direct:
Begins with Banjo & Kazooie, talks about their moves, stage with Gruntilda boss (her rhymes would be the codec replacements) and Mumbo Jumbo assist, all mirroring Simon's reveal. Echo fighters Ken and Shadow (okay, in my dream it would be Dixie and Shadow). Followed by the single player mode, that includes new stages, and this is where Minecraft pops up. We finally get a reveal of all 108 stages. Alt costumes are shown off, and there's a lot more than we expect, perhaps some bragging as to how many different combinations there are. New Pokemon/items/assists, and Incineroar pops up (okay in my dream along with Sceptile). Sakurai reveals the plans for DLC, and then has one more thing: Geno ends the Direct (I'll add in Boshi for Zinith). Seems so perfect, which is why it's not gonna happen.