To your first question, the answer is no. Subpart A of Regulation E covers EFTs in accounts that are maintained by individuals primarily for personal, family or household purposes.
To your second question, the answer is yes. Although Regulation E will not apply, your contract with Visa requires you to provide certain fraud and unauthorized transaction claims service to your business cardholders. That requires that your employees have some familiarity with the applicable Visa contract requirements, or that a third-party service provider be in place to handle the claims.