A lot of this depends on how you view the characters and their relationships, I think, but one other more prominent example is Hirut and Aster, who in various ways act as shadows of one another as they work together. Aster has greater social power and standing than Hirut, but she behaves as though she's jealous of Hirut, which suggests that maybe she (Aster) is the one who feels diminished and less capable.
I thought the photo described at the end of the introductory part of the book seems to capture the complexity of their relationship: The picture is of Hirut, and Aster is in the background ("so far away she is hard to see") but somehow still rises to significance in the description ("an elegant line cutting through light").