I haven't seen GO-GIRL, it was after my cut-off date. But Trina Robbins tried a few girl-oriented strips around that time, and they were light, pleasant fun (but forgettable).
The one who looks like Mary Marvel is supposed to be Little Lulu. They do have the same hairstyle but that's Lulu's dress and she belongs with Annie, Dot and Audrey better than Mary Marvel would.