It's fun to speculate who may be in wave 4+. I definitely think wave 4 will finish out the 3DS starting roster, which means:
- Olimar (REALLY curious to see how this amiibo looks, especially his space helmet over his head)
- Zero Suit Samus
- Charizard
- Greninja
- Palutena
- Pac Man
- Robin
So that's 7, and that might be it. We had a wave of 12, then 6, now 11 coming up, so wave 4 might be another smaller one.
But then the Wii U version had 4 extra starting characters with:
- Ness
- Jigglypuff
- Ganondorf
- Bowser Jr.
So they could be included in wave 4 as well, for another wave of 11. The 8 characters who were hidden in both versions were:
- Wario
- Falco
- Lucina
- Duck Hunt
- ROB
- Game and Watch
- Dark Pit
- Dr. Mario
I would bet on those 8 being all together in the final wave, possibly with Mewtwo as well since the DLC will be out in spring