Something I really liked sbout NtN was like, the casual Gender of it all. Pyrrha is a woman that Nona loves, a woman with strong muscular arms and a deep voice who shaves her face every day. Never once was it implied that there was anything... incongruous about it. (Of course, Nona never knew G1deon but she still could've wondered why she doesn't look like the many other women she knows)

The children call the Angel (who seems rather androgynous) "sir" not because they're confused by her presentation, but because its easier to call each teacher by different titles instead.

BOTH Kiriona and Ianthe use the title "Prince." Naturally it makes sense for the butch Kiriona, but Ianthe is very feminine and previously referred to as Princess. (Nona doesn't know this either, but its still A Choice on Muir's part)

Its subtle but noticeable. It shows this part of the world building without ever explicitly saying anything.