To expand my idea a little more ...
The Mighty Poo
Attacks: Based on classic martial arts moves and kung-fu, kicks and jabs, all fast and powerful as Poo's real ability to do damage and KO are not his specials but his martial arts training, a reference to his hand-to-hand focus in Earthbound.
Neutral Special: PK LifeUp, Poo meditates and slowly regains health, the effect is a slow but as long as Poo continues to meditate he continues to slowly recover health. The slow recover is also a nod to the HP system of Earthbound.
Side Special: PK Starstorm, unlike the Final Smashes of Ness and Lucas, Poo takes a more hands on approach to his PK, as he launches himself in a glowing aura of white light, acts similar to Fire Fox, and can be aimed in any direction as Poo takes a moment to charge, and can tilted slightly during its motion, leaves Poo in a helpless state after.
Up Special: PK Teleport, Poo slowly gains charges over time, similar to Wario's Down Special, the longer he waits the more charges he has for a total of maybe 3-5. This allows Poo to teleport without helpless state, he can freely acts out of Teleport, but teleports are short distance, possibly half the distance of Mewtwo's Teleport. If Poo has no charges saves up, he will always default to one charge as soon as he hits the ground or takes a hit.
Down Special: PK Shield, defensive move, Poo surrounds himself in a shield of psychic energy that protects him from attacks and expels foes away. It will not reflect projectiles, but will block them, but it will launch enemies away from him, similar to how Shine works.
As you can see, Poo's specials focus mostly on defense, mobility, and recovery, otherwise, unlike the other current Earthbound representatives, Poo is a very melee-oriented character, wanting to get into the frey, attack quickly, and withdrawl at a moment's notice when needed if he needs to heal or avoid counterattacks. His spcials aid his ability to use his martial arts in combat, but most won't do damage or be much of a finisher.
Also: his alternative costume can be based on his robot form from the end of the game! Since we got pajama Ness instead of Robo-Ness, this would be an opportunity for us to still get it in spirit by having Robo-Poo!