I agree with Don. Since POA's are governed by state law, you may wish to check the specific requirements too. The POA for buying/selling real property can be as simple as a simple power of attorney or as complex as a recorded specific power of attorney. If you sell loans on the secondary market, another source would be the loan investor. Ask them what their requirements might be.
I believe under CIP, you would have a lot of alternate ways to identify the borrower, credit bureaus, verifications of deposits, employment, mortgage, rent, etc. Check your bank policy for verification if the person does not have an ID.
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Integrity. With it, nothing else matters. Without it, nothing else matters.