MKE-MR Not confirmed means that there are no upgrades available for that flight and they cannot confirm the possibility of an upgrade. Waitlisted means that there may be places on the flight but there are none at the moment. But there is a reasonable chance that there will be later.

A lot depends upon passenger numbers in the requested cabin on the actual flight. I suspect that the not confirmed flight is a route with heavy traffic. Also remember that July sees heavy holiday traffic on most routes.

You will probably be upgraded on some legs but nothing is sure at the moment.