My ultimate list (roster want wise)
Nintendo
1. Krystal (assist trophy x.x)
2. Saki
3. Paper Mario
4. Demise
5. Lyn (assist trophy x.x)
6. King K. Rool
7. Tom Nook (final smash)
8. Blue (Second Pokemon Trainer)
9. Waluigi (assist)
10. Wolf Link and Midna (assist)
Honorable Mentions to replace those that are already deconfirmed
Porky
Impa
Black Shadow
Captain Toad
Isaac
Third Party
1. Banjo Kazooie
2. Spyro the Dragon
3. Crash Bandicoot
4. Sora
5. Master Chief
What I actually think will happen.
9 Newcomers Base Game
1. Inkling
2. Ridley
3. Arms character (new and they are gonna push it) (Twintelle, Spring Man or Ribbon Girl)
4. Mech Character (maybe Elma) (from mech/arm tweet thing)
5. Pokemon from new generation (they always do this)
6. Simon Belmont (leak)
7. Geno (Sakurai talks a lot about this character and we have cloud now)
8. King K Rool (costume and a huge fan base like Ridley)
9. Other Huge 3rd Party (Steve stage rumor so Hopefully Banjo Kazooie, popular with Nintendo fans) (Will be big surprise and super popular, probably high on poll)
3 Base Echo fighters
1. Daisy
2. Shadow (probably popular on the poll, easy to do no assist currently
3. Chrom (popular last game, got actively shunned but spotlighted, easy to do)
Dlc
1. Paper Mario (very popular, has many games)
2. Dixie Kong (super popular, easy semi clone)
3. Rayman ( Ubisoft is willing and works a lot with Nintendo)
4. Isaac (no assist, been wanted for awhile by fan base)
5. Crash Bandicoot (remaster on switch, Super popular)
6. Spyro ( remaster soon, probably coming to switch, popular with same crowd as crash)
7. Heihachi (Bandai Namco, Harada would be pleased I imagine)