Introducing the Echo characteres: (name obviusly bassed in SSBU) they are characters that you can get, beating challenges, they are part of SC but they aren't canon.

Characteres:
FnaS Styled New Sonic as Echo Character of New Sonic
Male New Yoshi as Echo Character of New Yoshi
Toy La Enchilada as Echo Character of New Mario
Frost Toy Tails as Echo Character of New Tails
FnaS Styled Rusty Sonic as Echo Character of Rusty Sonic
Rusty Boshi as Echo Character of Rusty Yoshi
MT Mario ad Echo Character of Rusty Mario
and Casino Kitsune Luigi as Rusty Tails Echo Character
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I may add more in the future but don't ask me to add any random character, if I add another Echo character in the future I want that o be my dessicion