The names of the fields can be whatever you like on the front end.
Call them Bob, Sam and Sue for all the module cares. The examples made in the documentation are just that--examples. The hierarchy of your regions is independent of what you call it, which is the beauty of the module.
You can have any depth of regions in a hierarchy, although I think 4-5 is probably what most folks would ever use.
So all use cases you describe above are supported.