I think it is more than just a Catholic concept. My recollection is that Samuel Rutherford was Presbyterian or something. John Locke started as a Calvinist.
The British had their own version of "natural law." To them, it was "natural" that the King would rule over other men, and that he was chosen by God to perform that task, and disobedience to the King, was tantamount to disobedience to God.
Rule by "Divine Right."
This is a different foundation for their natural law than that which America adopted.
They all started as Catholics, or their ancestors did, and the modern sense of it (natural law) comes straight through Aquinas, whom they probably read. Or they got it via someone else who got it via Aquinas.
“Divine right” is another matter. The Catholic view is in fact that “natural law” trumps “divine right”, as does, well, actual divinity. It is a limited concept and not part of any conception of “natural law”.