It is easy to figure out. sujets = subjects and naturels = natural born. So when the founders read "naturels" in Vattel's passage on citizenship, it's PLAIN to see that he was talking about natural born citizenship. Thanks again for proving you are wrong.
“Sujets naturel” is a phrase, just as “natural born subject” is a legal phrase, not 3 words that just happen to be next to each other. No one should translate “naturel” as “natural born subject” or “natural born citizen” unless the rest of the phrase is there - and in Vattel, it was not.
That is why the first translations had, “The natives, or indigenes...” - and BTW, it was indigenes that was translated NBC in the 1797 mistranslation.