In terms of version of control, a workbook that is created in an earlier version, can be opened in a newer version of Tableau. However, a workbook that is created in a new version of Tableau cannot be opened in an older version. I'm not sure that I completely understand the basic requirement--so let me know if this does not answer your question.
For question 2, user filters may be able to be used to give each region their respective data:
You can also give them access to the data at different times--by manually setting the permissions.
Hope this helps!
Hey Phillip -
We allow the customer to choose and leverage the source control application of their choice to do this work. Since our workbooks are nothing more than XML documents, you can use whatever app you choose to manage multiple versions of the same doc.
We currently don't have a way of doing user/group specific resource governing.