You don't say where your various families lived, so this comment may or may not be relevant.
Kuntz is one of the names I've seen among "Palatine" (German) migrants who arrived in American in the early 1700s. I think there have been several immigrant families by this name who arrived in America at different times, from German-speaking parts of Europe. I've seen the name spelled other ways, including Kuhns, Coons, Counce, Coontz, Koonce, and other variations.