Need some help - rear brake overheating? 1967 C10

[Knanthrup]

I'm having a frustrating time diagnosing some issues. What I thought was one problem appears to have turned in to two separate problems. I started hearing a squealing sound coming from mid or rear of truck, related to drivetrain not engine. I thought it must be the drum brake hanging up or potentially a wheel bearing. My suspicion was further convincing when I felt the rear wheels and the drivers rear wheel was extremely hot to the touch. I dug into the brakes and sure enough the left rear shoe lining was smoked, looked like it got baked at high temp. The passenger side looked totally fine. I cleaned up the parts and put new shoes on and test drove it. Noise is still there.

Further investigation and it seems like the squealing noise is coming from the center driveshaft carrier bearing rather than the brakes or axles. Ok so at least the noise seems to be identified, but now I can't figure out what is cooking the brakes!?

After my test drive I felt the drivers rear wheel and again it was wayyy too hot.

So I'm having a hard time figuring out whether the brake is hanging up or if the heat is coming from a failing wheel bearing or something else. There is no noticeable vibration or sound coming from the axle itself, but there was also no noticeable issues with the brake hardware that would cause the shoes to drag.

Any thoughts?

Below are pictures of the fried brake shoes (please note that the cracking may have been caused by me using a heavy hammer on the drum to get it unfrozen - not sure either way, but clearly it had taken a lot of heat). Also photo of the brake hardware assembled before I replaced the shoes, just in case anyone can spot something wrong with the hardware or setup.