As a kid I really liked SATAM and hated AOSTH, the former sadly was the one that was always on and I would rarely catch SATAM. Then around the Gamecube era I started watching AOSTH on Toon Disney and started to like it but I really wanted to watch SATAM after all the praise it got, when the DVDs finally came out and I got to check the show out I was disappointed by how average it was.
It's not that it's a bad show, it just doesn't compare to other 90s greats like Gargoyles or BTAS while it's praised as if it were. On the other hand I was able to appreciate AOSTH more. Now Sonic Underground I like that it exists but boy was it terrible,
here is my review of all three DIC Sonic Cartoons I did a long while ago and I think in that link you can also find how I fit all three DIC cartoons in the same continuity
and Sonic X/OVA review.
Having the Freedom Fighters being a faction Sonic interacts from time to time would be awesome, have the original SATAM cast as a team, hell add Sonia/Manic from Underground to the team, it can have the original or re-designs and have them come from the city of "Mobius", that would be the best way to handle it, you can even add some dialog for Sally when meeting Sonic "Oh, it's nothing, I just felt as if we had met before" or whatever to appease fans that the other happened in another universe.