When I did mine a few months ago I noted that the front caliper attach bolts were short. Lacked thread engagement so I installed longer bolts.
Yes, the new rubber boot retaining rings lack spring tension. Probably Chineese mush metal so I reused the old ones. I carefully glued the boots in place before installing the retaining rings. Be careful of the nylon slide. They get brittle with time so I replaced them.
Bleeding was a pain until I bought Motive Products power Bleeder. It made for a first round KO. It takes a high flow rate to purge trapped bubbles. The fluid can harm some paint so be careful. Get extra shims so you can center the caliper to discs. The alignment on mine was poor.