Like all films, characters go through many designs before a final is decided. Here I will post the phases the characters have gone through down to the final character design.

Lady's development

Lady has gone through some changes, but not as nearly as many as say Tramp did.

Tramp's development

Tramp here has gone through many phases before turning into the Tramp we all know today!

Jock's development

Jock didn't go through much of any development at all!