That is a question which is hard to answer.
Kiyohime is to begin with 14 years old while Astraea is a god and very old. This would mean that they prob not be a couple but good friends that is a possibility.

Astraea and Eresh are both godesses of different domains and while the are using vessels of Luvia and Rin that had a rivalty. there is still a possbility for them to be friends. That is ofc if they aren't summoned as enemies.