I knew as I was reading this post the name KOCH stood out to me and so I kept coming back to it. I just finished reading all you wrote.
YOUR HERTZEL was my father's "Hartsell" ancestor who'd stayed in PA when John (son of his father's brother) left for NC back around the mid 1700's.
ok..this is too incredible.
I sat down to open up my "Hartsell/Hertzel/Hartzel/Hartzell/Hirzel history and the page I opened to is the history of the Hertzel/Koch union that ended up with the land that is now owned by Bethlehem Steel..
which quite amazingly is right across the river from the Ettwein ancestors who'd started the Moravian community in the same place.
Anyway, I have a whole lot of history for you if you haven't yet traced your ancestors any further back than your Maria Elizabeth HERTZEL Koch. I have all the Hertzel side of that union and much of the Koch side as well right in front of me as it was written by a Hartsell cousin who spent her lifetime doing research on her HARTSELL roots.
Maria Elizabeth HERTZEL KOCH is one of a few Koch ancestors who are part of our family tree.
If this can help you are welcome to write to me Karenkolbin@gmail.com
There are at least two pages of Koch family ancestors in our Hartsell History
All from Northampton (Bethlehem and Nazareth) PA