The appointment requirements of Section 37.004 do not apply to:
(1) a mediation conducted by an alternative dispute resolution system established under Chapter 152, Civil Practice and Remedies Code;
(2) a guardian ad litem or other person appointed under a program authorized by Section 107.031, Family Code;
(3) an attorney ad litem, guardian ad litem, amicus attorney, or mediator appointed under a domestic relations office established under Chapter 203, Family Code;
(4) a person other than an attorney or a private professional guardian appointed to serve as a guardian as defined by Section 1002.012, Estates Code;
(5) an attorney ad litem, guardian ad litem, amicus attorney, or mediator providing services without expectation or receipt of compensation; or
(6) an attorney ad litem, guardian ad litem, amicus attorney, or mediator providing services as a volunteer of a nonprofit organization that provides pro bono legal services to the indigent.