@Paula Knight some of this depends on Courses versus Learning Plans. In a, Users - Courses report (under New Reports) you can report on things like Course Enrollment Status that you can then decide what statuses you want to report on.

In that same report you can see a range of course statuses.

Hope this helps, your question covers a few areas.

@Paula Knight - You can definitely report on enrollment status. I collect all enrollment status (enrolled, in progress, completed) so I understand my denominator at any given moment (allowing you to generate a rate or % incomplete). I then use a little bit of pivot table magic to support the rest. This is not complex or difficult and you can use a template and refresh your pivot table to act as a type of dashboard view.

Soon - Learning Insights will become available and something like this will be a little more configurable/manageable on the fly.

I think you will find a challenge taking into account people that are on leave without bringing in that level of detail into your learn instance. If you are? Then definitely bring that into the number that you build.