There is going to be a lot more newcomers than some think and there is going to be cuts.
The thing is, you can't say any of that for sure.
We have no idea what the development of this game is, what the background information of the game is, or anything other than Inklings, Mario, and BOTW Link. We know nothing.
There's obviously a chance for cuts. However, how can someone say that for sure when the dev cycle started shortly after Wii U, takes place during the launch cycle of a new console and death of the previous, and is already close to complete?
Speaking in absolutes has a way of biting us. I would be cautious. The development timeline is different for this game than effectively any Smash game, save for arguably Melee.
I'd say wait and see before we determine if there are cuts or not. As of right now, there's no way of telling.
As I've said before, I think it's entirely possible this game started as a "port this to the new console as quickly as possible with added new things" and turned into a full fledged "let's make this game amazing" by preserving as many of the characters as possible (if not all) from Wii U, and updating those models and stages and what not to be more current.
I also think it's odd, in the case that Nintendo wouldn't attempt to broker the deal for a character like Cloud for a sequel
they know is coming in the next few years. If you're going to acquire freaking Cloud, why wouldn't you make sure he was in the title that would be in the sights of far more fans rather than a one-off DLC for a dying console?
Also, if money is an issue, why even bother acquiring him in the first place? It's not like Nintendo is hurting for cash anyway.