At one point in time, I remember writing "Authorized signer only" beside the names of authorized signers on sig cards for DBAs and businesses. Is that required, or is typing "Authorized Signer" after their name sufficient?

What if their name is appearing in the "owner" section of the signature card rather than a "authorized signer" section? Does that cause a problem?

These are all contractual issues that should be vetted through your attorney.