When before or at the hearing on any proceeding in a probate court it appears to the court that the interest of a person unborn, unascertained, or legally incompetent to act in his or her own behalf, is not fully represented, the court may appoint some competent and disinterested person to act as guardian ad litem, or next friend, for the person unborn, unascertained, or legally incompetent, and to represent his or her interest in the case. The person so appointed shall make oath to perform his or her duty faithfully and impartially, and shall be entitled to such reasonable compensation, out of the estate, for his or her services, as the court may allow. In any action involving wills, estates, trusts or fiduciaries in the probate court, a minor, an incapacitated person or an unborn or unascertained person whose identity and location is unknown and not reasonably ascertainable, unless otherwise represented, may be represented by and bound by another having a substantially identical interest with respect to the particular question or dispute, but only to the extent that: (1) the person’s interest is adequately represented; and (2) there is no conflict of interest between the representative and the person represented.