For Nancy Springer, I'd also suggest Larque on the Wing.

I'd add Neil Gaiman's graphic novel A Game of You. Major characters include a lesbian pair and a transgendered woman. Trigger warning: transgendered woman finds herself excluded from participating in certain activities due to lack of ovaries. I feel the author's reasons for including this plot point were sound, and that his overall treatment of the character is poignant and respectful, but I'd like to put this warning out there.