I noticed a lot of constellations resemble from earth zodiac. Could add to them to have all 12 in expansion. Just an idea and maybe not a good one. It would feel a little funny to have earth things in cairn. Could be explained like Steven King explains why Dark Tower and others of his books have elements from Earth in different universes. Or could just drop the lore explanation of zodiac and even have alternate lore. For example the Lion could have nothing to do with the Nemaen Lion or The Twins nothing to do with Castor and Pollux and make up new lore. Zodiac does in a way fit GD lore in the sense that astrology is a bit of an ‘occult’ thing.
Ok so signs we have: Bull, Crab, Lion, Scales, Scorpion,
Maybe: Huntress, Keeper of the Waters
Nope: Ram, Twins, Virgin or Maiden, Goat, Fishes