We have opened LLC account and LLC has 20 members. Not all 20 members are authorized signers on the account. Do we still need to obtain rest of all members' information (CIP)?
how about on the LLC resolution? Are we required to get all members signature on the LLC resolution?
Thanks.

Rest of members' info? -- Depends on your bank's CIP requirements.

I see no need for all the members to sign the resolution.

My experience with many-membered LLCs is that the agreement names a small number of "managing members" (or similar designation), who are authorized to handle money, open bank accounts, etc. If your customer's agreement has such a provision, then those will likely be the members that you will want to sign the resolution.

And you need the LLC organization docs to know this. My bank asked for mine!