Because hes one of my favorite characters, I put together a little walkthrough of what Pac-Mans special moves most likely are.
Standard Special Move - Fruit
Hold B to cycle through the various fruit Pac-Man collected in his original game, and then release the button to throw the fruit. Like Diddy Kongs peanuts, fruit can be eaten to recover health.
In the trailer, we see Pac-Man cycle through the fruit in order of their value. It could be surmised that the cherry recovers the least amount of health while the melon recovers the most. The Boss Galaxian is used as a weapon instead of recovering health, obviously, and we dont know if the bell or key are included.
For reference, here is how much the various items are worth in the original Pac-Man:
Cherry (100 points)
Strawberry (300 points)
Orange (500 points)
Apple (700 points)
Melon (1000 points)
Boss Galaxian (2000 points)
Bell (3000 points)
Key (5000 points)
This is just a prediction, but maybe the cherry recovers 1% health (100 points), the strawberry recovers 3% health (300 points), and so on. That would be a fun little nod.
Side Special Move - Namco Museum
Perhaps as an homage to the various retro game collections and cameos over the years, a Namco arcade classic appears in the palm of Pac-Mans hand. Like his neutral B, these also seem to be scrollable. Each object has a unique function reflecting the source material. In the trailer, we see:
Pellet (Pac-Man)
Spaceship (Bosconian)
Pooka (Dig Dug)
Mappy (Mappy)
Andor Genesis (Xevious)
There are likely a few more selections; perhaps the Boss Galaga shown is one of them.
Up Special Move - Trampoline
Taken from the retro arcade game Mappy, Pac-Man tucks into a ball and bounces off a trampoline. Just like in Mappy, the trampoline breaks on the fourth bounce.
Down Special Move - Fire Hydrant
The fire hydrant from Pac-Land appears as a special move. Similar to Villagers tree, I assume pressing down B next to it opens the valve to release water. It can also be struck and sent flying as a projectile.
Final Smash - Power Pellet
Pac-Man eats a Power Pellet and turns into a giant retro version of himself. It is presumed that he can K.O. opponents in this state by eating them.
In summary: Pac-Mans move set is fucking awesome.