Also, other humans would be introduced in a possible 4th season but they look like furfags because something-something nuclear annalation something-something radiation turing some humans into mobians and Mobius was actually earth the entire time. Not to far off from Archie comic actually. Except with less echidnas.
Sorta. Offscreen nuclear war caused animals to mutate, creating Mobians, while humans... It was an unknown. Some would be mutants too (like Eggman), while others would be the regular deal.
Archie had the bonkers idea that conquering aliens visited Earth, then Robotnik's ancestor dissecter the ambassador and the aliens responded by throwing gene-bombs at the planet, destroying all life (except for those hiding underground), and creating Mobians and Overlanders from the mutation.
The first idea fit more with the post-apoc vibe SatAM had. Meanwhile, in Archie the critters somehow got access to an offbrand plane stolen from the X-Men.
his own "finding himself" arc and possibly joining up with the Freedom Fighters.
And then betraying them, possibly, only to be stopped by Antoine, who would eventually become useful.
There would be another over arching plot dealing with Nicole's origin and that woul also play into it somehow, but I think that was for the movie idea though.
Which was grimdark to the max and more interesting than what the comic did: Instead of being a random AI that Sally stumbled upon, Nicole used to be a little girl Mobian that Robotnik copied her mind into a machine, then destroyed her body (while she was still watching) because it was no longer needed, all part of an early experiment at robotization. Then Sally stumbled upon said machine and became friends. Nicole herself erased these memories because she would go ballistic and murderous, understandably.