This deserves stressing: if you ever have to recover your multisig wallet you'll need:

• the required quorum of private keys (e.g. 2 of 3); and
• the xpub of ALL co-signers, i.e. 3 xpubs in case of a 2 of 3 setup.

People have lost money because they did not properly back-up all co-signer xpubs.