(1) A power vested in two or more trustees shall only be exercised by their unanimous action; provided, however, that a cotrustee may delegate to one or more other cotrustees the performance of ministerial acts;
(2) If a vacancy occurs in the office of a cotrustee, the remaining cotrustee or cotrustees may act unless or until the vacancy is filled; and
(3) While a cotrustee is unable to act because of inaccessibility, illness, or other temporary incapacity, the remaining cotrustee or cotrustees may act as if they were the only trustees when necessary to accomplish the purposes of the trust.