(1) the validity of the purported custodian's designation;
(2) the propriety of, or the authority under this part for, any act of the purported custodian;
(3) the validity or propriety under this part of any instrument or instructions executed or given either by the person purporting to make transfer or by the purported custodian; or
(4) the propriety of the application of any property of the minor delivered to the purported custodian.