The straight brown,brownish hair throws me after awhile with almost all the 70s missing. after awhile, they all look like sisters to me. I was a small child then, so remember when this was The Look.
I think April was too fair to be The Girl in The Fur Coat. Her description notes her hair as "red", although it looks more brown in photos, but her skin is light, and even a bit freckled in some pics. I think the girl in the white turtleneck looks fairskinned. She has brassy hair. The photo of April staring directly looks a bit similar to me, and the runaway reference, height, build and timeline fit.
My opinion is TGITFC is Jewish, or maybe Italian? She looks very "New York" to me, as someone raised in the East Coast. Hopefully this doesn't offend anyone. I don't mean it to at all. It's just a feeling I have. There's something about her appearance that reminds me a bit of friends of mine.