There's also the fact that we haven't seen ANY Miqo'te at all among the Domans. It's Yugiri and then a bunch of Hyur. I can't imagine, if Miqo'te originated in Doma, that ALL of them left Doma to migrate to Eorzea. There would still have to be even a minority population, and at least a few should have survived the Garlean razing of Doma.
But the whole thing is speculation anyway, so, *shrug*.
But the whole thing is speculation anyway, so, *shrug*.