If an interested person is a minor or an incapacitated person as defined in section 524.5-102, subdivision 6 or 10, or otherwise under conservatorship, and does not have a guardian or conservator within the state, the court shall appoint a guardian ad litem for the person. If an interested person is unborn, unascertained, or a person whose identity or address is unknown to the petitioner, the court shall represent the person, but the court may, upon the application of the petitioner or another interested person or on its own motion, appoint a guardian ad litem to represent the person.