Time for my very safe and worthless final prediction roster for the base game because why not
Chrom - My only extra echo fighter. Popular, but Sakurai doesn't seem to find him unique. Thus, in a very similar boat as Daisy.
Simon Belmont - classic iconic game series. Sakurai likes it. I think the rumour has some credibility. I wouldn't be surprised if he was a dark horse popular demand.
Bandana Dee - popular with the majority of the Kirby fans gunning for him. I think he's likely, but not guaranteed.
Lycanroc - Sakurai will give himself some liberty and add a fighter he finds unique. GameFreak will tell him about Lycanroc and Mimikyu, and I can see him going for a terraformer with rock moves as an unique fighter.
Elma - Mostly due to the toy mech being bought, but also since Xenoblade is filled with potential moves and has grown substantially since Smash 4. Another character seems imminent.
King K. Rool - I kind of doubt that his worldwide popularity matches the results we see online, but if it does...kind of a no brainer for a last reveal/hidden character to me.
Yeah I am boring but eh, nobody gets these right anyway.