Your friend should consult with a criminal defense attorney as soon as possible . Then he should deal with the warrant because as stated it will not go away and the court will be more favorable if he deals with it rather than being arrested.
You need to hire an attorney to defend you on the domestic abuse charge, if you were arrested and charged with that. You should also talk to perhaps a civil attorney with relation to the automobile and whose name is on the title to the car with intention of getting it back.
If the facts are as you present, it may be that the prosecutor will not go forward and dismiss the case. However, since charges have been made by the police, it is not the simple matter you think it is. If you are very low income or indigent, the court will appoint a very competent attorney to handle this for you.
This definitely sounds like intimidation and entrapment. As the others stated definitely talk to a supervisor at the State Police headquarters.
The public defender is your attorney. If you feel he is not on your side, ask the judge for a change of attorney. Speak to this attorney about your feelings in this matter.
As far as the civil theory of "social host liability" you would need to contact a civil litigator. He was responsible for his own activity as far as the charge of DUI and the social host liability law does not usually extend into the criminal charge arena. The fact that he was not a minor also negates this theory somewhat. He should talk to an attorney and try to plead this out.
It does not seem likely that you would pay for her criminal attorney. She should have had one appointed. Only if your assets are still together and they were used by the judge in determining if she could have a court appointed lawyer would your money be involved. Discuss this with your divorce attorney.
Your question might better be directed to a Pennsylvania attorney board. From the facts you've given your case falls under PA jurisdiction. Discuss it some more with your PA attorney. The fact that this involves monitoring means that the county in PA would be responsible for that and it is not likely that NY would want to take on that responsibility.