The rule is, you're natural born if you are entitled to citizenship by birth. Ted Cruz qualifies, even though he was born outside the US. As does John McCain. As did Barry Goldwater (born in Arizona before it became a state). As did George Romney, who was born in Mexico of American parents. They all qualify, despite being born outside the soil of the admitted States of America.
Now, Ricky Sanchez was born in Guanabacoa, Cuber, a township of Havana. His parents got him here as soon as they could, but, sooo sorrry, that's not good enough under the Constitution!
As a citizen of both countries, Brett Hull could have played in international hockey tournaments (Olympics, World Championships, etc.) for either country. The International Ice Hockey Federation, though, has an important rule that only allows a player to compete for one country in his lifetime. So once Hull decided to compete for Team USA, he was permanently ineligible to compete for Team Canada.
It seems practical for a U.S. law -- or even an amendment to the U.S. Constitution -- to be drafted in a way that contains some kind of clarification for presidential eligibility.
Where is that rule stated in any legal code applicable to the United States?
No, that is not the rule. The rule turns on whether your citizenship depends on an act of Congress.
If the rule was as you claim, then children born to alien parents who are legal residents of the Virgin Islands, are NBC. See 8 USC 1406.
Who issued Rixks BC ? The state department of the country of Cuba ?