It would be nice if there was a dictionary from 1787 that contained the phrase. Unfortunately there isn't. But we can look at how the term was applied in various laws.
Here are the Massachusetts Acts of naturalization (before the ratification of the Constitution individual states could naturalized individuals):
In February, 1785, the Massachusetts legislature passed “AN ACT FOR NATURALIZING NICHOLAS ROUSSELET AND GEORGE SMITH.” in which it was declared that Nicholas Rousselet and George Smith “shall be deemed, adjudged, and taken to be citizens of this Commonwealth, and entitled to all the liberties, rights and privileges of natural born citizens.”
In February, 1786, the Massachusetts legislature passed “AN ACT FOR NATURALIZING MICHAEL WALSH.” in which it was declared that Michael Walsh “shall be deemed, adjudged, and taken to be a citizen of this Commonwealth, and entitled to all the liberties, rights and privileges of a natural born citizen.”
In July, 1786, the Massachusetts legislature passed “AN ACT FOR NATURALIZING JONATHAN CURSON AND WILLIAM OLIVER” in which it was declared that Jonathan Curson and William Oliver “shall be deemed adjudged and taken to be free Citizens of this Commonwealth, and entitled to all the liberties, privileges and immunities of natural born citizens."
In March, 1787, the Massachusetts legislature passed “AN ACT FOR NATURALIZING WILLIAM MARTIN AND OTHERS.” in which it was declared that William Martin and Others,”shall be deemed, adjudged and taken to be free Citizens of this Commonwealth, and entitled to all the liberties, privileges and immunities of natural born subjects.”
In May, 1787, the Massachusetts legislature passed “AN ACT FOR NATURALIZING EDWARD WYER AND OTHERS THEREIN NAMED.” in which it was declared that William Martin and Others,”shall be deemed, adjudged and taken, to be free Citizens of this Commonwealth, and entitled to all the liberties, privileges and immunities of natural born subjects.”
In October, 1787, the Massachusetts legislature passed “AN ACT FOR NATURALIZING BARTHOLOMY DE GREGOIRE, AND MARIA THERESA, HIS WIFE, AND THEIR CHILDREN.” in which it was declared that Bartholomy de Gregoire, and Maria Theresa, his wife, their children,”shall be deemed, adjudged and taken to be free Citizens of this Commonwealth, and entitled to all the liberties, rights and privileges of natural born citizens.”
In November, 1787, the Massachusetts legislature passed “AN ACT FOR NATURALIZING ALEXANDER MOORE, AND OTHERS, HEREIN NAMED.” in which it was declared that Alexander Moore and others,”shall be deemed, adjudged and taken to be free citizens of this Commonwealth, & entitled to all the privileges, liberties, and immunities of natural born subjects.”
In June, 1788, the Massachusetts legislature passed, “AN ACT FOR NATURALIZING WILLIAM MENZIES, AND OTHERS, THEREIN NAMED.” in which it was declared that William Menzies and others “shall be deemed, adjudged and taken to be free citizens of this Commonwealth, and intitled to all the liberties, privileges & immunities of natural born subjects.”
In November, 1788, the Massachusetts legislature passed, “AN ACT FOR NATURALIZING ELISHA BOURN, AND OTHERS, THEREIN NAMED.” in which it was declared that Elisha Bourn and others “shall be deemed, adjudged and taken to be free Citizens of this Commonwealth, & entitled to all the liberties, privileges & immunities of natural born Citizens.”
In February, 1789, the Massachusetts legislature passed, “AN ACT FOR NATURALIZING JAMES HUYMAN, AND OTHERS, THEREIN NAMED.” in which it was declared that James Huyman and others “shall be deemed, adjudged and taken to be free Citizens of this Commonwealth, and entitled to all the Liberties, Privileges and Immunities of natural born subjects.”
In June, 1789, the Massachusetts legislature passed, “AN ACT FOR NATURALIZING NATHANIEL SKINNER, AND OTHERS, THEREIN NAMED.” in which it was declared that Nathaniel Skinner and others “shall be deemed, adjudged and taken to be free citizens of this Commonwealth, and entitled to all the liberties, privileges and immunities of natural born subjects.”
In March, 1790, the Massachusetts legislature passed “AN ACT FOR NATURALIZING JOHN JARVIS, AND OTHERS, THEREIN NAMED” in which it was declared that John Jarvis and others, “shall be deemed adjudged and taken to be free citizens of this Commonwealth, and entitled to all the liberties, privileges and immunities of natural born subjects.”
In March, 1791, the Massachusetts legislature passed“AN ACT FOR NATURALIZING JOHN WHITE & OTHERS" in which it was declared that John White and others, “shall be deemed adjudged and taken, to be free citizens of this Commonwealth, and intitled to all the liberties, privileges, and immunities of natural born subjects.”
If what you posted were taken for all that it entails. Then where someone was born or to whom someone was born is no determination to being a natural born citizen. Those persons mentioned must of had to have met some unstated criteria. Otherwise Anyone could have been declared a natural born citizen. Who were those persons, and why were they declared citizens at all. We simply don’t know.
This makes no relevant point. During this period in History, the terms were regarded as interchangeable, though a citizen and a subject have very different characters. “Subject” eventually fell out of usage.