Just curious, were all four hubs that stopped rotating cartridge bearing hubs, or were any cup and cone? I saw in your next post you identified Phil hubs, thus cartridge bearing, but it is not clear to me if you had any cup and cone hubs stop rotating?

Were all hub problems rear hubs, or any front hub problems?

Was your Surly front rack your only rack failure, or did you have any other rack failures? If so, any conclusions on what to avoid? I expected some rack failures to appear in this thread but a word search did not find any others.

Thank you for the extremely detailed posts.