I think people fundamentally misunderstand the way third party DLC characters are added to Smash. Of course I can never be 100% sure of how the industry works, but the way people seem to think it works is that Nintendo goes to visit a company, asks "which character do you think should be added?" and then the company decides it. I don't think that's how it happens. I think it's more likely that Nintendo has a meeting to decide the characters by themselves and then goes to ask each company for permission, and then the companies can change the character if they would like.
I feel like it's just a lot more likely. Like do you think Sega would be like "yeah the top three characters you have to add are sonic, bayonetta and joker?" No, I think it's mostly Nintendo making the picks. I mean, Sakurai literally said Nintendo does make the picks.