I bought a wifi boroscope camera that connects to my phone with a 1/4 inch lighted camera on the end of six foot long flexible line, only $32! Seemed like a natural way to inspect inside the bell housing to learn more about our clutch and mouse next issues.
Here's some pictures of the throwout bearing, first are two on the side towards the transmission:
Then here's one of the engine side of the throwout bearing which includes a partial view of the clutch diaphragm:
We don't see any issues with the throwout bearing or clutch from these views. Looking around further though we did see more evidence of mouse nest residue:
Plus we removed about a partial handful of stuff using our usual method of pulling the rubber boot back and trying to snag stuff with a piece of baling wire.
Bottom line is we still think the clutch is fine and the residue is somehow causing the squealing under particular conditions. So monthly inspections will be continuing!