Run them. The photos do not show anything that would concern me. Yes they do get hot at that speed and mass to stop. Often the brakes are used casually and seldom see had braking.

You have sintered metal pads on a metal disc. The few gouges are there and will be fine. As for the howling and screaming, sometimes the brakes are not clean, especially if the timing chain has or careless chain lubing has contaminated the disc. The brakes may have had a hard time building friction and this did not help matters. Even dust from the brakes and road will lessen the brakes effectiveness.

In regards to lost performance concerns, clean them and reinstall. Make certain the vibrations did not shift the caliper on the spherical mounts. If they got hot enough to melt the adjusters, replace them. Honestly, I do not even see abnormal overheating or discoloration of any concern.

FWIW, I just had a look at he discs on both tandems, we have more "lines of use" than the photo you posted.

PK