No person shall be designated or serve as an emergency interim successor unless he may under the Constitution and Statutes of this State and the Charter or Ordinances of this County, hold the office of the person to whose powers and duties he is designated to succeed. No provision of any ordinance prohibiting an officer or employee of this County from holding another office shall be applicable to an emergency interim successor. Any person designated as an emergency interim successor holds that designation at the pleasure of the designator; provided that he must be replaced if removed. He retains this designation as emergency interim successor until replaced by another appointee of the authorized designator.