The answer to your question depends on your legal status with your children's father. Were you married? If so then he does have certain rights to the children. If you were not married, then his legal standing is much different. I would tell you to contact an attorney and bring all of your relevant paperwork prior to any move.
In the State of Missouri you have the right to file for an Adult Abuse Order of Protection if someone is stalking, harrassing or hurting you. Upon filing said Order, a Judge either grants it or denies it. Either way, you are granted a court hearing and date. At the hearing you have the right to a hearing. The other side will have to put on evidence to show that you have indeed stalked, harrassed, hurt, etc. that party. The Court's have to follow state law and cannot issue an order just because.
It sounds like you have a very complicated case right now. I am glad you have an attorney. You are going to need a lot of paperwork to prove your case. The Judge is going to have to make several determinations as it relates to child support. First, if child support really stopped four years ago. Second if your and when you child is emancipated. Either way, I would ask for attorney's fees.
You don't say if your case is final yet. If your case is not final, you still have the chance to find a different attorney to represent you. If you have alleged abuse or neglect in your pleadings the Court has to appoint a Guardian ad Litem to represent your daughter. This could help your case in protecting your daughter.
Missouri is what is called a modified no fault state. Further, Missouri does not have what is called community property, we term it as separate and marital property. Any property or debt you had prior to marriage is separate. Whatever property or debt you accumulate during marriage is marital. Issues start to arise when you "comingle" the funds, or use separate property to pay for marital items, or vice versa.
In the State of Missouri, you only have to make your son available for a DNA test unless you agree or you are ordered to by the Court. The biological father must file a Paternity action and request a DNA test which he will be required to pay for at the time it is administered.
In Missouri the Family Court judges use the standard of what is in the best interest of the child. From your description, it does not sound as though your ex has acted in your son's best interests. However, the ex still does have custody rights. You will need to have a judge determine if he should have supervised contact with your son. If supervised visitation is successful, it may be the Judge wants to move to unsupervised contact. When your case is heard at court, because you have...
In Missouri it is very difficult to have your parental rights terminated unless there is just cause or someone is stepping in to take the role of that parent. If you signed paperwork giving your ex wife physical and legal custody that does not mean you have had your rights terminated. It sounds like you have agree that she will have sole legal and physical custody. You still have rights to your son, including visitation.
In the State of Missouri a father does not have any legal custody rights to his children until it is established through a court order. A DNA test, a paternity affidavit, nor a child support order can change that. In Missouri in a paternity a Mother is assumed to have sole legal and physical custody of the child with all visitation time. That means the Mother can move anywhere at any time and does not have to noify Father. It sounds like you need to establish that he is legally Father, set...
Your wife will need to see an attorney, experience in these matters, to help her best address how to deal with the back child support. If she is receiving child support through the State of Missouri, they will have an accurate printout of how much is owed, and if there is a current garnishment in place. Also, if the amount progresses above a certain level, it becomes a criminal matter. If your wife wishes to proceed in the Family Court, she will need to file a Motion for Contempt and Order...