Most players outside this forum won't know what "Odrysians" are, so I think Thracians works best, just based on the Odrysian kingdom and also some traditional Thracian units as your roster indicates.
Thracians and especially Dacians should for sure be added. I will reiterate my opinion that Empires Ascendant should just go ahead and add the later "Part 2" civs to the game. "Part 2" being so far away, it would essentially be its own game and then you might as well go with a different time period, like Medieval or Bronze Age.