(1) Each trust agreement shall specify the following: Its duration;
(2) The number, qualifications, method of election, and terms of the trustees who shall serve as the governing body of the trust.
(3) Each trust shall have a minimum of seven (7) trustees.
(4) Only current elected officials and active or retired employees of a local government or of a local government association may serve as trustees.
(5) A majority of the trustees must be officials or employees of participants.
(6) Each trustee shall be elected by the participants for a term not to exceed three (3) years.
(7) The terms of office shall be staggered so that at least one-third (1/3) of the trustees are elected each year.
(8) Each participant shall be entitled to one (1) vote in each election of trustees;
(9) The qualifications, terms, and conditions necessary for additional local governments to become parties to the trust;
(10) The terms and conditions under which local governments may withdraw as parties to the trust; provided, that any party shall have the unconditional right to withdraw upon not more than ninety (90) days' notice;
(11) The permissible methods for acquiring, holding, and disposing of real and personal property used in the operation of the trust;
(12) The maximum amount of funds of participants the trust may accept for investment;
(13) The permissible methods to be employed in accomplishing the partial or complete termination of the trust and for disposing of property upon the partial or complete termination;
(14) The terms and conditions under which the trust agreement may be amended and supplemented; and
(15) Any other necessary and proper matters.
(16) Each addition of a local government as a party to a trust, each withdrawal of a local government as a party to a trust, and each amendment or supplement to a trust agreement shall be evidenced by a written supplement to the trust agreement.