@Merry Andrew,
Youre right, the SUsquehannocks and Conetoga werent MEMBERS of the Iroquian Alliance but they were descended from the stock which displayed the "long house" dwellings and they spoke Irooquian root language. Wallace(1964) , posed that the Susquehannocks, Minquas and Conestogas were descended from the tribes of the Huron and Mohawks and , when all the various tribes claimed areas of the Ohio and Momongahlea, the "Black Minquas" (Susquehnnocks) wiped out their own connecting tribes that would have extended the Iroquois Alliance southward. So, yep, no Iroquois Alliance membership , just Iroquaois stock and many of the same artifacts and lifestyles.
I agree that Wayne did not encounter any Lakotas or any Plains Indians. It was more likely that, had he had a mistress, she would have been Cherokee from when he lived in the SOuth after the Revolution.