But it's also something of a red herring, because it tricked me into spending longer-than-I-want-to-admit trying to figure out whether Radchaai characters were male or female,

Whereas I went 'every significant character is female unless otherwise noted, screw you patriarchal-brain-colonizing fiction tropes'.

Anaander basically marriage-of-convenienced them without even asking Breq.

Huh. I interpreted that as Breq being adopted into the family, as was often done in ancient Roman family what a promise person was spotted by a family without an heir.