There is no "magic age" in Arizona when a child can decide between parents. The ultimate test is what arrangement is in the child's best interest. The older, the more mature, the more articulate a child is in stating their preference, then the more weight is given to their choice, but it is not the only factor - see ARS 25-403 for the list of other factors.
Also consider having a "Parenting Coordinator" appointed in your case. That person is usually at least master degreed and appointed by the court from a pre-approved list. Their function in to referee disputes like yours and make recommendation to the court on action to be taken. The costs are usually shared and you can have one appointed on your own by visiting the superior court's self-help center in your area.
No. I have found that the more mature a child is, and the better able the child is at articulating his or her choice, the more weight is given to their preference. Regardless, the court's concern is always the child's best interests, not just what the child wants.
Yes, unless the Court determines the public interest in disclosure is outweighed by the privacy interests of the persons concerned, i.e. you need to make a compelling argument your circumstances are much different from the standard divorce.
If you purchased the car for cash from your separate funds, and if the funds were not commingled with community funds, and if her name does not appear on the title, and if you did not gift the car to her, it's probably yours to keep.
Arizona Rules of Civil Appellate Procedure 9 and 10 provide that your Notice of Appeal and $500 cost bond must be filed with the Clerk of the Superior Court not later than 30 days after entry of the judgment in your case, unless a different time is provided by law. Consult an experienced lawyer immediately.
Great question which highlights your concern over privacy and potentially his indirect stalking of you versus a father's concern for the safety of his son. There is no absolute answer, although I would question Father's true motivation. But expect your ex-husband to argue: Why should you care if you have nothing to hide, and doesn't the GPS provide one extra layer of safety? It's a close call, however, any excessive calling during your time is not.