Why not just have the characters that the masks from Majora's Mask turn you into? I forgot their names in the game, but there's enough things that each one does to give them a moveset, such as these:
Deku:
up-b: Shoots up into the air with flower in each hand, similar to Peach's up b
side-b: Spins in circle, similar to Ice climbers's side b.
down-b: Throws Deku nuts, similar to Peach's down b.
neutral b: Charges bubble, similar to Samus's neutral b.
Goron:
up-b: Spins in air, similar to DK's up b.
side-b: Becomes a spiky ball, rolls at enemy, similar to Yoshi's side b.
down-b: Drops on enemy, similar to Bowser's down-b.
neutral b: charges punch, similar to DK...