I have the valve to the return closed as well.

Right now the cinder block pad the pump sits on is wet from the pot overflowing. I wouldn't be able to really tell a leak in the pot or its immediate fittings unless there is, as you say, a dribble. And what with the rain coming this plumbing leak detection event may have to be on hold for a few days.

What I do know is there's no evidence of water at any of the valves or connections to/from the pool nor any visible leaks in the pump fittings.