While I'd personally prefer Tails or Knuckles as the second Sonic rep, since Knuckles is now an Assist Trophy and Tails unlikely as a newcomer, I'll gladly take Shadow as an Echo Fighter of Sonic. He honestly fits the bill for that role more than any other character in the series in my opinion, even Metal Sonic or Classic Sonic. I discredit Metal because he rarely uses any of Sonic's attacks or anything similar outside of Spin Attacks, and Classic because of height differences (and honestly "Modern" Sonic in Smash now I feel represents the character well enough). Shadow, while still being the most diverse from these three, he shares more with Sonic at the same time in attacks and properties (ala SA2). Also, as far as I'm aware, Shadow is still the 2nd most popular character in the franchise behind Sonic, especially to the younger demographic, so I think his spot would be more than well deserved. The only problem he faces is being a 3rd party and the potential 1st 2nd rep for a 3rd party (that's a lot of ordinal numbers), but he still has my support. And if you guys didn't mind, I'd love to share my personal moveset of how I'd see Shadow as an Echo Fighter.