my income is below filing threshold
Nothing to do with taxes, but it raises questions on how you provided more than half of the child's support for the entire tax year.
When it comes to taxes, you have to follow the IRS rules. Only a federal judge can over ride the federal tax laws, and since federal judges do not deal with divorce or custody cases, that will never happen. What a lower court says or decrees holds absolutely no weight with the IRS since the IRS is governed by federal tax laws. You have to follow the IRS rules with no exceptions.
