I can't comment on everything, but I can correct one point: Doma rebelled against the empire because the current emperor had just died, making them think they had a chance with a surprise attack while the Empire was dealing with a succession crisis. It failed and Doma was razed for their trouble.
Edit: I guess I can also add the Chocobos are only native to Eorzea. It's not impossible that some could have been imported into the empire before trade relations were dissolved, but I doubt something like a rare steed would be used as a beast of burden by a travelling merchant.
Edit: I guess I can also add the Chocobos are only native to Eorzea. It's not impossible that some could have been imported into the empire before trade relations were dissolved, but I doubt something like a rare steed would be used as a beast of burden by a travelling merchant.