-If you have a tool that can constantly two frame (in Steve's case, down tilt), use it. It will force him to recover high with Homing Attack which you can dodge and punish.
-Speaking of which, shielding Homing Attack will actually let him get away with it. But if you dodge right when he's about to fly to you, he'll bounce off the floor and you can hit him with basically whatever.
-There are a lot of ways to deal with Spindash, but the method I use is just staying away and baiting him to release. Then if you time it right, you can grab him or hit him with a long lasting move. Maybe Steve's down smash could work in this instance?
-Try to stay offstage if you can or else "Sonic's Back Aerial" will be engraved on your tombstone.
-Juggle him and bait him into airdodging. All Sonic mains like to airdodge because they have one of, if not, the best directional airdodge in the game. If you can bait them into dodging a certain way, then you can cover where they land.
-If Sonic puts a spring below your angel platform, just jump around it.