At least 15 days before the hearing of a petition for administration of a decedent’s estate, the petitioner shall serve notice of the hearing by mail or personal delivery on all of the following persons:
(a) Each heir of the decedent, so far as known to or reasonably ascertainable by the petitioner.
(b) Each devisee, executor, and alternative executor named in any will being offered for probate, regardless of whether the devise or appointment is purportedly revoked in a subsequent instrument.