Yoshi and Birdo cosplaying as Ichigo Momomiya

Akin to MUGENhunter's Tails

2/3 of them are references to

Sonic's Concept and is also a Skin in Sonic Superstars Cream's Debut (Though inconsistent looks)

A former 90s rival's (A red capped plumber guy) recent 3D platformer since 2017

Early previews of "Shining Wine (Not alcohol)" and "Castle Party"

Continue. But classic

Another mechanic that I coded for the first time

"Grab Canceling"

The only thing that varies between character is: how long will they actually throw the opponent while Pressing Y + Holding FWD/Pressing Z + Holding Backwards will still do the cancel trick

The Classic Hop and Dive. (Amy Rose)

The "Big Green Man" (Guest) teaser.

Despite being Water (Or Mutated Chao) slime sounds

Act Music as Rounds? (may not apply to every stage)