I would suggest that the best place for you to look for the correct meaning of "natural citizen" is not a court case over a century after the fact, but in the words and deeds of the Founders.
Those who know what the term mean were those who passed it in Congress, and those who ratified it in the state legislatures.(Here are the names of the men to whom I refer.)
Subsequent lawyers who were not involved in the process are not primary sources. William Rawle is particularly bad because he was NOT a DELEGATE, because he was the Son of a British loyalist,(British Mayor of Philadelphia.) trained in England in explicitly British Law, and motivated by his adoption of the abolitionist agenda (He was President of the Abolition Society of Pennsylvania) to push the British law interpretation of citizenship so as to make a legal case for the emancipation of slaves. (He attempted this before the Pennsylvania Supreme Court, and failed. This same strategy was successful in Massachusetts though.)
But he wrote the most famous textbook on the Constitution, and thereby mislead thousands of others who followed.
This from the guy who uses as two of his major sources David Ramsay, who wasn't at the Constitutional Convention either, and whose views on citizenship were slapped down 36 to 1 by James Madison, half a dozen other Framers, and our first House.
And Samuel Roberts, who not only wasn't a Constitutional Convention delegate, he didn't even have any known direct connection to any of the major Founders or Framers.
Rawle was a close personal friend of both Washington and Franklin, met with them and other Founders for months in Philadelphia leading up to the Convention, was asked to be US Attorney General by President Washington, was appointed US District Attorney for PA, and was one of our major early legal experts.
“William Rawle is particularly bad because he was NOT a DELEGATE, because he was the Son of a British loyalist,(British Mayor of Philadelphia.)...”
Actually, his step=father (Samuel Shoemaker) was the British Mayor of Philadelphia. His real father (Francis Rawle)died when he was about three.
“... trained in England in explicitly British Law, ...”
As were many of the Founders. In fact, one of the Framers, Charles Cotesworth Pinckney, attended the same London law school as Rawle (Middle Temple). Mr. Pinckney also attended the lectures of Justice William Blackstone, the author of “Commentaries of the Laws of England”.
“... and motivated by his adoption of the abolitionist agenda (He was President of the Abolition Society of Pennsylvania) to push the British law interpretation of citizenship so as to make a legal case for the emancipation of slaves. (He attempted this before the Pennsylvania Supreme Court, and failed. This same strategy was successful in Massachusetts though.)”
Benjamin Franklin (a Framer) was also a President of the Abolition Society of Pennsylvania (at the time it was called the Pennsylvania Society for Promoting the Abolition of Slavery). He sent Congress a petition in 1790 asking them to abolish slavery.
John Jay (not a Framer, but author of the “Permit me to hint” letter) was also an abolitionist (although he argued for a more gradual freeing of slaves). In 1777, he introduced legislation to end slavery in New York. In 1785, he was President of the New York Manumission Society. As the Governor of New York in 1790, he signed An Act for the Gradual Abolition of Slavery.
If we limit ourselves to just Framers there is this:
Alexander Hamilton: In a 1795 legal brief on carriage taxes, Hamilton begins by saying it is shame that some terms in the Constitution are ill-defined. And he ends the brief by saying, “... where so important a distinction in the Constitution is to be realized, it is fair to seek the meaning of terms in the statutory language of that country from which our jurisprudence is derived.”
Oliver Ellsworth: As Chief Justice of the Supreme Court in the 1797 district court of Connecticut’s Case of Isaac Williams wrote, “The common law of this country remains the same as it was before the revolution.”