Mary Melodie is, of course, from "Merrie Melodies". I don't know who the heck Shirley's supposed to be based off of.....perhaps that female duck in that.....uh.....y'know, the episode with Daffy's owner, Agnes, and her father. Does anyone know what the H-E double hockey sticks I'm talking about?!
Other than that, I think you pretty much covered it. I think.
And besides, most people look at this type of topic unrealistically. They are all under the apparent misconception tha--oh, wait. Is my post over? Ah, okay.