Ugh, so tired and Pikmin are running through my field of vision... Off the top of my head. Trying to avoid too much rolling to keep him unique as compared to Sonic (and Dillon, if he were to be in).
Up Special: Rev Launch - An aerial variant of Pac-Man's Rev Roll technique, holding the Special Attack button will cause Pac-Man to hang in the air and spin, building momentum. Realeasing the button launches him at full spin through the air. Direction can be angled with the joystick. (Pac-Man World 2/Original)
B: Chomp - Works like Wario's biting attack but with knock-back instead of munching. (Pac-Man)
Side Special: Sonic Blast - Pac-Man lets loose a series of sound waves which can stop projectiles and deal light damage to enemies, though it halts their forward progress. (Pac & Pal)
Down Special: Bounce-Pac - Works like a Ground Pound move, but tapping the B button will allow Pac-Man to bounce continuously. He can move sideways in this manner, but as a consequence of mobility the attack is very lightweight and has poor priority. (Pac-Man World 2)
Final Smash: Super Pac-Man - Most people have Pac eat a Power Pellet and become temporarily invicible while he munches away at foes... I'm mixing that with his heroic alter-ego, SUPER PAC-MAN! Dawning a red cape and tripling in size, Pac-Man becomes quite a force to be reckoned with.
To answer your second question: Siegfried from Soul Calibur, and Lloyd Irving from Tales of Symphonia are both viable alternative reps, as is Taizo Hori or Mr. Driller. None of them really hold as much water as Pac-Man does, and I'd be legitimately disappointed if they got in over him. The only Namco character who should be near Pac-Man level priority is KOS-MOS, as she's an iconic SciFi JRPG character and the face of the Xenosaga trilogy, which has indirect connections to Nintendo's own Xenoblade Chronicles.