Actually, our Kuhn book does not talk about Peter Kuhn's life in Germany at all. It only mentions that he was from Württemberg. There are some descendants of Peter that have hired a German researcher to find out more about his background, but nothing has come up yet.
The book I own only covers Peter Kuhn and his descendants, so there is no information prior to 1748. As for the location information you mentioned, Katholisch means Catholic. Braunsbach is the village, Jagstkreis is the district (like a county), and Wuerttemberg is the state. I no longer live in Germany, but I have traveled all around the Black Forest area and you do see the Kuhn name everywhere, still. I'm sorry I'm not more help!