He can sound tough without having a baritone voice. That would just scream "animated movie" and or "stunt". He's a tiny raccoon and his voice should reflect that.
Edit: buscemi, a real actor who has a higher voice but can (and has repeatedly) play tough, could actually work. He has nothing in common with Sandler so not sure where that came from. Nobody is suggesting a comedian as far as I know.
Edit: looks like Sean Gunn is getting the nod so its moot now. If I remember from Gilmore girls, he was anything but tough sounding. Its called ACTING, which is way better than typecasting a familiar voice because you think it would sound cool and amusing coming out of a raccoon. That would be the wrong approach imo, which is why I'm relieved they're going in a different direction.