Within 30 days after a petition to adopt a minor stepchild is filed, the court shall serve notice of the proceeding upon:
(1) the petitioner’s spouse;
(2) any other person whose consent to the adoption is required under this article;
(3) any person described in subdivisions 3-401(a)(3), (4), and (6) and subsection 3-401(b) of this title; and
(4) the parents of the minor’s parent whose parental relationship will be terminated by the adoption unless the identity or the whereabouts of those parents are unknown.