I don't expect a lot of IPs in this installment, but if I had to list all of the most probable ones:
- Rhythm Heaven
- Pilotwings
- Puzzle League
- Bomberman
- Castlevania
- Puyo Puyo
- Shovel Knight
Characters: Rhythm Girl, Pilot, Lip, Bomberman, Simon Belmont, Arle Nadja, Shovel Knight.
Arle Nadja could have the potential to represent both Puyo Puyo and Tetris because of the crossover. Lip has the potential to do that as well.
As for Pilotwings, I would expect Lark to appear as a playable character, but under the name "Pilot". Kind of like how Popo & Nana are referred to as Ice Climbers or Tap Trial Girl would most likely be Rhythm Girl.
He could be the first character who uses a jet pack as his main weapon. There's also other weapons in his arsenal such as the bird suit, hang glider, rings, parachute, and a Gyrocopter that fires missiles as a Final Smash.
Maybe Dillon or Chibi-Robo could happen too. I'd like to see some more relic/gem characters.