As I've pointed out before, "Tiny Toon Adventures" was a much better show than it's given credit for. Take, for instance, this early segment featuring Sylvester, Furball, and Lil' Sneezer. Not only is this one of the first times we hear Joe Alaskey voicing Sylvester, it's also the debut of Sneezer, one of the only Tiny Toon stars patterned after a classic character NOT owned by Warner Bros. at the time. Clearly inspired by Chuck Jones' Sniffles the Mouse, Sneezer never appeared alongside his "mentor", presumably because all of the Sniffles cartoons were then owned by Turner.
Also note that Furball is cast as a young protege of Sylvester here. In later episodes, the character became less derivitive of his mentor and more of an original character. While he occasionally talked in early episodes, that idea was eventually dropped entirely, and he became a completely pantomime character, something then unheard of in made-for-TV animation. He eventually became Elmyra's long-suffering pet, and the host to a family of Italian fleas. He also appeared in a couple of surprisingly touching cartoons as a homeless alley cat in search of a home, which many fans believe were created by Steven Spielberg himself.