These are educated guesses based on what I’m predicting they’ll add. Nintendo is notoriously hard to predict so there’s a 99% chance I’m wrong but it’s fun to try. Also the order I’m listing them in is not the order I think they’ll be releasing in.
Paper Mario – The PM series hasn’t been selling nearly as well as you’d expect something with “Mario” in the title to sell, and its got a game coming up pretty soon that could probably benefit a lot from Smash advertising. That coupled with the fact that he’s pretty well liked and has had a decent bit of fan demand makes me think he’s just about the safest and best character they could add right now.
Travis Touchdown – Very similar situation to Paper Mario. NMH3 is coming soon, Nintendo is publishing it I think, it could use the boost, fans want him. Overall it all just works out nice for him.
Steve – We’ve not yet seen a really popular character that this pass can use to sell itself, and I can’t see them not having one. I can’t think of anybody better f0r the job than Mr. Minecraft himself. It’s especially easy to see since the bridge of Microsoft content in Smash has been crossed already thanks to Banjo-Kazooie.
Another First Party advertisement character – Yeah this probably seems like a bit of a cop out, but I do think they’ll go for this but nobody in particular comes to mind. I don’t think it’d be a Pokemon as that game really doesn’t need the help and there are a lot of games that could use it more. I reckon it’ll be from a 2021 game that hasn’t been announced yet, which is why I’m not gonna pick a specific character.
Waluigi – Alongside Steve, I think Waluigi will be the character they try and sell this pass on. I really don’t think the assist trophy matters, especially not after Min Min. Waluigi is one of, if not the, most requested character, and an extremely easy character to include due to being a first party Mario character. Him being an assist trophy caused the biggest uproar over a character not being in smash that has ever happened. His inclusion would definitely get a lot of attention.