Definitely rotational. I'm with John on this one.

Ordered new rear axles and joints. Kits don’t show that the circlips come too, just the bolts (?)

Should be an assembled unit. Clips and all. Be careful with bolt length. Can be 45mm or 50mm. You don't want them protruding out the back of the flanges, especially on the outers, where they can bind the rotation and damage the seal on the axle bearing. Good idea to use schnorr washers too.,

The Loebro kit has 47mm. I’ll be sure to check that when installing. Plan to do right around the 4th and will update this thread. Thanks again for helping me track this down.

Late update. I installed the new axle set a few weeks ago. Used the Schnorr washers. So far no more noise. Checked the allen bolts a week or so after driving, and all were still tight. Thanks again for the help!