The third, fourth, fifth, sixth and seventh members shall be selected and appointed by the Township Board from among the electors residing in the unincorporated area of Grosse Ile Township, for a term of three years. Such third, fourth and fifth member shall not be an employee of the Township Board nor an elected officer of the Township. Of the third, fourth, fifth, sixth, and seventh members of the Board of Appeals first appointed, one shall be appointed for a one-year term, one for a two-year term, and one for a three-year term. Thereafter, such members shall be appointed for three-year terms. Terms shall expire on April 1. A vacancy on the Zoning Board of Appeals shall be filled for the remainder of the unexpired term in the same manner as the original appointment.