Yes if it's a TV series. It could be a movie though, still unclear.
I doubt Shadow will get his own movie. And that won't be a bad thing because I imagine Knuckles TV series is like Knuckles having his own movie but in parts.
It'll be nice if it's Chaotix but wouldn't that make the budget too high since there will be lot of CGIs?
It's cheaper if it's using a human enemy like Agent Stone.
What we would have is a "high risk, high reward" sort of thing. Yes it would cost more money to render, animate and voice the Chaotix but the fans would appreciate their inclusion.
Or else, if the Knuckles TV series would just be Knuckles and Wade goofing about across half of America, then while it would be amusing, fans still expect more from a TV show about Knuckles than just Wade and Knuckles sharing a braincell together.
Hayden Christensen rumored to be voice of Shadow in Sonic 3
Article : https://www.dexerto.com/tv-movies/hayden-christensen-rumored-to-be-voice-of-shadow-in-sonic-3-2487956/
Meh. Never heard of him and don't matter if I did.
Not difficult making a Shadow impression so they literally could have gotten anyone to do it.