An application for approval of a PUD may be filed by a person having an interest in the property to be included in the planned unit. The PUD application shall be filed in the name or names of the recorded owner or owners of the property included in the development. However, the applications may be filed by a holder or holders of an equitable interest in the property. The applicant must show evidence of full ownership interest in the land (legal title or the execution of a binding sales agreement) before final approval of his plan. When a joint application is made for a PUD, the project must be in single ownership by the time the final development plan is approved.