Natural Born Citizen means born on US soil with US citizen parents, plural. Was hashed out into infinity on the 0bola research threads. Used to be that when a foreign national woman married a US citizen husband she automatically became a US citizen but those days are long gone.
You are certainly far more the expert on all that.
However, IIRC, the Supreme Court has declared that Congress can declare the details of what constitutes definitions & criteria etc. Assuming big GOP win in 2020, those variables could be changed.
The US soil part has an exemption. The child, being born in a foreign country to 2 US citizens abroad ^in service to the USA^, is considered born on US soil and is an NBC.
McNoName