The District shall include only commercial property located within the city for which the owner thereof has submitted an application to the District and has agreed to the inclusion of such real property in the District, and for which the owner has submitted documentation, in a format approved by the District, evidencing the written consent of each person holding a first mortgage lien on the property. An owner may apply for and enter into agreements for the inclusion of real property, as provided in § 4-11-4. Inclusion of property in the District may occur at any time subsequent to the formation of the district. Real property shall be included in and assessed by the District as described in § 4-11-6.