Can the owner, President and Director also be the Registered Agent of a small company?

Yes, an individual within the company can be the registered agent of the company. I would refer to the Texas Secretary of State's FAQ on the subject for more information. Best regards, SR.

Yes, the same person may hold each position in a company, with the exception of partnerships. Then, at least two persons are required. Yet again, though, the partners could be two entities owned and controlled by one individual.

Yes, as long as the person or company consents to being the registered agent. The purpose of the registered agent is to receive notices for the company, such as notices from the state or service of process for potential lawsuits. Therefore, almost anyone, including owners and officers of the buisness entity may serve as registered agent.

Yes, so long as the address that is used is a physical address, no PO boxes may be used for registered agents.