Louisa May Alcott - I had forgotten her. One of the few children's authors I think to successfully cross back to this side of the pond. (Actually that is an interesting thought in its own right, you may export your moving media to us, but the written word does not travel with even remotely as much ease and if anything we seem to export more to you. Hmm, I wonder why that is.)

Insofar as homosociality in American children's/YA lit, one would best look to books like the BabySitters' Club ones (which have a decent-sized femslash fandom for a book fandom) which focuses on close-knit groups of female friends, I think. That's the sort of tradition The Squad is coming out of, I think.
This makes sense in a culture where education tends to be mixed and female sport has become invisible. Most female homosociality would have to focus directly around friendship rather than pre-arranged social groupings.

Yeah, very interesting stuff to think about. Thanks.