Q: Can we add map layers ourselves? And if so, can we administratively determine if those layers are created locally and/or would propagate to all user maps?
A: Yes, you can add map layers to your heart’s content. Ideally, your department has a reliable IT or GIS person comfortable with ArcDesktop. They can then modify the map file the program is pointing to. If you do not have an experienced IT person, our GIS department can add map layers for you.