Are the above really considered bank "customers" for CIP purposes? Our insurance agent is an employee of the bank, but the products he is selling are from third parties. Similar situation with Brokerage, the agent is an employee of the bank but he sells his products through a third party. Also for mortgage, we take in the application but the mortgage is subsequently sold.

I worked for a Fed regulated bank, and our regulators expected our insurance agency to abide by the same BSA policy as the bank. We did, however, have a separate CIP policy for them,as they are only required to perfrom CIP on "value retained" products such as annuities and whole life insurance. Keep in mind that insurance companies are considered financial institutions for CIP purposes, and if your Agency does not abide by your CIP policy (or even if they do) they may still be required to abide by the insurance company's policy.
Our brokerage services were offered through a 3rd party, and our employees were dual employees of both the bank and the brokerage. When opening brokerage accounts, they abided by the brokerage's policy, because they were acting on behalf of the brokerage.
Your mortgage employees must abide by your bank's CIP policy, even if you sell the loans. Your bank is establishing the relationship, so mortgage applicants must be identified and run through OFAC by the bank.