Kevin,
There will definitely be clans and social structure within the clans. There will be a few major clans to choose from, but players will also have the choice to come from a lesser known, smaller clan if they wish to come up with their own ideas and submit them for approval. If you guys see the finished local race packet, and would still like to flesh out your clan with suggested structural names, you can feel free to create a smaller clan as long as it fits within our vision. As for Warhammer, I would prefer if you don't use the EXACT names, but feel free to be creative and come up with different/similar ones.
If you have any other questions, shoot em my way. You can also email me privately.
Chat soon,
Jesse