There is nothing odd or unrigorous about the fact that a citizen at birth is by definition a natural born citizen.
You’ve acknowledged that the several States determined birthright citizenship differently, curiosity.
So? Anyone who was a birthright citizen of at least one state was a birthright citizen of the United States. Whether he would have been considered a birthright citizen by the criteria of some other state was immaterial.
There was not a State in the nation, that would have deemed a Presidential candidate born abroad of citizen parents eligible.
Nonsense.
And, there were several States that would not have deemed a Presidential candidate born in one of the several States eligible, if that candidate was born of a foreign father.
That is simply not true. States never had the authority to determine who is or is not eligible to be president. So long as a person was a birthright citizen of at least one state, that person was eligible, regardless of the citizenship laws in other states.
Please cite the Constitutional Article and Clause stating this, curiosity.