About Little Mac's uppercut (Up + B), why not base it on one of Luigi's B-moves. Namely base it on how the Super/Flaming Jump Punch works for Luigi.
If Mac's timing is off, the uppercut only does light damage (around 3-5%). If Mac's timing is spot on, the uppercut becomes the Star Uppercut and deals serious damage (around 30-35%). Though this could hinder Mac's ability to recover unless the Melee's version of Luigi's Super/Flaming Jump Punch is used as the concept.
If Mac's timing is off, the uppercut only does light damage (around 3-5%). If Mac's timing is spot on, the uppercut becomes the Star Uppercut and deals serious damage (around 30-35%). Though this could hinder Mac's ability to recover unless the Melee's version of Luigi's Super/Flaming Jump Punch is used as the concept.