How to delete/remove a manager?
 

I cannot find this anywhere.

I had an owner quit my league but I cannot remove him from the team nor can I delete him permanently.

What am I doing wrong? Where do I do this at? Surely there's a way to do it... right?!?

From the Manager-Basics-Manage Human GMs screen, right-click on the name of the guy you want to remove and you'll get a "Remove (Name)" option.

When I did this it said options for the selected manager. Not the one I was hovering over. Is that a bug then?

Yep. Its just a bug. When right-clicking on a GM's name it still says the active GM's name but you can in fact delete the one you're hovering over.