Hi @Duileoga,
These look really good!
@wowgetoffyourcellphone and I are interested in developing these nomad civs for vanilla 0ad.
For the xiongnu, I really like 3 of your buildings for the role of "royal yurt". Also, the barracks, stable, and market would do great. I see you have a lot of permanent buildings too. I have tech for the xiongnu called "han diplomacy", and its basically meant to unlock some of the influence from the Han dynasty. So for the dock, it would be really cool to start with a simple yurt-based boat yard (basically what you have here, but with a small boat frame or skeleton on the ground near the yurt), and then upgrade to the dock here with the tech.