I think we should look at their history. Thier home system was overrun by their mistake, which could explain why they are now nomadic, get still technologically advanced. Of course, they have been nomadic for centuries and so have adapted to that life. I don’t think it necessarily means they have adapted in terms of their bodies. Because they are so advanced, they would have been able to adapt their ships to suit them.
As for life, I think it should be almost completely in space. Perhaps the ships we have seen are only small elements of their fleet, and they actually have colony ships, similar in size to our stations, where the tribes live.
Perhaps as another idea: thinking on the native american role, their ships have things that they can set up to link them together to make a larger colony of ships which remains within an area of space for a time (thinking of the teepees american indians are assosiated with from history), still able to move. When travelling longer distances they pack up and move on.
I think too they might possibly be quite guarded on their own history and technology. Revering it and protecting it in order to preserve some of their old ways.