I have moved your post over to a new thread since it seemed to be a very different topic than the original post.
I think this is a bit too much to deal with in a single post, you may get some advice on some of these points but I think it would be best to try and break out some of the topics to make it more approachable. For example, you mention the subsite URL structure you would like to use. This may be a good topic for discussion as a thread. I have not implemented any thing quite like this myself and it is not functionality that any WebAssist tools will create for you. So I think on at least this topic you should post some more specific questions and include any examples or references for the functionality you are describing. This should allow more forum visitors a chance to see your topic and chime in if they have anything to add.