Notice of the hearing of an application for approval of any such sale or agreement, or both, shall set forth the date and place of hearing said application, the purpose of said hearing, contain a description of the land involved and refer to the application for further particulars. Ten (10) days prior to the hearing date, notice thereof, together with a copy of the application and all exhibits thereto, shall be mailed to the heirs, devisees and legatees of such deceased person or to the next of kin of said minor or incompetent. Notice shall also be given by publication one time in a newspaper in said county. If the leasehold or interest therein to be sold or included in an agreement covers lands situated in any county other than that in which the probate proceeding is pending, then such notice shall also be given in the county where said lands are located in the same manner and for such period of time as provided above. Proof that notice has been given as herein required shall be filed with the court. Notice by publication required herein may be waived by the court for good cause shown.