The probate court, on the filing of such report and statements, must appoint a day, not less than 30 nor more than 60 days therefrom, to hear and determine the same and must give notice to the creditors of and to all persons interested in the estate of the filing of the report and the day appointed to hear and determine the same by publication, once a week for three successive weeks, in some newspaper published in the county or, if none is published therein, in a newspaper published nearest to the courthouse of such county, and by posting such notice at the courthouse door for the same length of time and by forwarding such notice by mail to all creditors and to all adult heirs or distributees whose places of residence are known, and shall appoint guardians ad litem for all heirs or distributees who are minors or of unsound mind. Upon the day appointed or on any other day to which the hearing is continued, the court must proceed to hear and determine such report.