Yes, that's right. The public keys themselves don't grant permission to spend of course, so you can make many copies.

A multi-sig backup scheme could look like the following:

1: HWW #1 + Seed #1 + xPubs #1, #2, #3
2: HWW #2 + Seed #2 + xPubs #1, #2, #3
3: HWW #3 + Seed #3 + xPubs #1, #2, #3

Where the seeds and xPubs are stored on laminated paper.

Multisig requires the x/y/z Keys to be backed-up too, correct?

Fabs

Dude, that'd trigger my paranoia to the max.

yes, that is good. but an encrypted backup you can just email yourself is good too imo.