I'm not too sure about that - Sonic's priority leaves a lot to be desired. Sonic can get in no problem, it's just separating them in the midst of their aerials that can be a problem. I could try coming in with a fair, but I don't know if the IC's nair would stop it - I don't know much about the "trading hits" part of aerials to know for sure. But last I checked, the matchup was a 50:50 split, maybe 55:45 IC's favor. But not a harsh counter/shutout.
Brawl them on the ladders? So AiB goes by a ranking system or something? Sounds too much like Street Fighter or Mortal Kombat's system XD.
I want to take on some high level Sonics, Olimars, and Wolfs, just to see how they play, since I'll get crushed by them anyway. And maybe look at how the Warios fight as well - I was just messing with him tonight, and I really like his air speed and air game XD.