The viewers of Japanese historical drama or historical manga are not understand the court relationship. Otherwise, the story is rather confusing. The royal court or harem is more or less mirroring ancient Japan's politics. The local lords gained the power to rule Japan, by marrying their daughters to the ruling monarch. The family feuds of Japan's royal court might become civil wars. The princes or lords who lost power have to become monks or exiled far away from the court.
The world view of gold raven/crew is bit confusing. Reading Wikipedia article on mythology still doesn't answer much of the confusion.
https://en.wikipedia.org/wiki/Three-legged_crow
The characterization is easier to understand. The daughter of the eastern lord is a simpleton. It is more or less her limited contact with people outside her family. In contrast, two daughters of other houses are rather rude and ambitious. Then, the daughter of the fourth house is rather indifferent. She is there just to make up the number. Maybe they can play mahjong.