How can I collect on an over payment, when I don't have to anymore child support

The only way to recover overpayment is to sue in civil court.

There is no way to challenge the arrears at this point.

Unreimbursed medical expense

Generally, the statute requires that those expenses be shared. However, you need to make an application to the Court. If you do not have an...

Would he get joint custody?

As a practical matter, not very. He has to demonstrate a chance in custody. Moreover, the court will not grant joint custody without an agreement....

Does NY have some rule that child custody be resolved within 90 days? What about other states?

There is no such rule in NY.....................

Is my ex responsible for back childcare?

If the order is for him to pay, then he needs to pay. You can recover his share, but you will need to hire an attorney and take him to court.

In the case of an uncontested divorce should I file for a fault or no-fault divorce?

As my colleague stated, trying to do a divorce yourself especially in circumstances such as yours is very ill advised. That being said, every...

Will I get child support I never received before I was 18?

Unless there was a child support order, you will not be able to receive child support from the past.

Temporary sole physical custody after custody agreement?

Considering the age of your son it is very possible that your ex could win custody. If you wish to fight this then you need to start speaking to...

Did NY have legal jurisdiction. Agreed to custody agreement due to misleading info. Can I have the case vacated moved to NC.

You timeline indicates that the home state would remain in NY as the child never spent 6 months in NC. Moreover, once you consented to NY...