(a) A minor child is a permissible party, but is not a necessary party to a proceeding under this article.
(b) The court shall appoint a guardian ad litem to represent a minor or incapacitated child if the child is a party or the court finds that the interests of the child are not adequately represented.
(c) The court shall appoint a guardian ad litem to represent a defendant who is a minor and who is not otherwise represented by counsel.