Who is "we"? The court should accept your parenting plan as you agree (no mention of a father here) unless the best interests of the child overrides that somehow.
Whether a protection order can be relaxed depends on why the order is in place and who asked for it.
A power of attorney allows someone to sign your name on legal documents. All you need to do is create the POA form and sign it in front of a notary. The POA is not a custody document.
I would add that protection orders will not be modified unless the party being protected against can prove that there is a significant change in the circumstances that spurred the protection order in the first place.
It sounds like you and your mother came to an informal agreement for the custody of a child or children. Is that correct? How is the court involved in this informal agreement? Are there formal proceedings for a nonparental custody order or guardianship underway? Is CPS involved in the case? More information is needed to answer your initial question.
Also, I would suggest recatagorizing it as a Family Law question, as power of attorney is the wrong legal term for your situation. Feel free to email with questions.
