Alright, last evaluations.
PROS:
- Recent Nintendo IP
- Nintendo's first fully original mobile game, giving it a degree of significance and appeal towards the casual/mobile market
- Has absolutely no base game representation whatsoever, which is odd considering how we got deep picks like Goku and Girl from Hajimari no Mori or whatever her name was
- Gets enough push to have crossovers with big series like Mega Man, Monster Hunter, and Persona 5
CONS:
- Apparently makes less money than other Nintendo mobile games, like Fire Emblem Heroes
- Nintendo quoted as wanting to shift focus away from the mobile market
- Unavailable in Europe outside of the UK
- Potential competition from fellow Cygames creation Granblue Fantasy, which shouldn't be too hard to get the rights to
Overall: Has a bit of work to put in, but I think he still has a fighting chance. I'd keep my eye on him if I were you
PROS:
- Popular request for Smash, especially in Japan apparently
- Consistently appears throughout the series, moreso than almost any other character (From KSSU onward and only counting the main games, more than even King Dedede and Meta Knight)
- Consistently depicted alongside the main trio
- Made to represent the Waddle Dees, which are the second closest thing to a third pillar.
- Potential upcoming 3D Kirby game gives incentive to push the series
CONS:
- DLC doesn't seem to favor already-represented series.
- Nintendo could see Kirby as being represented well enough already
Overall: Might need to put a bit of work in to get there, but he seems to be in a pretty decent spot, all things considered.
And that's the last of 'em. As I mentioned before, the majority of the first-parties I went over suffer from some combination of not enough content for a full pack, not having incentive to push their content, not being on modern consoles, deconfirmed by post-launch content from their series, or competition that would push them out of priority. From what I can gather, I think the ones who have at least a decent shot are Rex, Euden, and Bandana Dee, the latter two not seeing as much attention. Maybe we should look into them a bit more closely.