Don't understand your question totally. You asked about a GAL. What for? You asked about the issue as to when no one has applied for custody. Why haven't you filed the papers for divorce and for orders on custody and visitation? You have the opportunity to do something but it appears that you have decided to be passive. What legal issue is the child trying to bring before the court?
You state that "no one has applied for custody", but you also state that a prior order was vacated. As long as your child is a minor, the original case remains open. Who was the GAL appointed for? Which child and for what purpose? Is there a pending hearing? Why haven't you filed for divorce or at least for custody orders yet? What are you waiting for?