Catching only parts of the Kartenberg saga, I wish to offer another possibility.
I believe that Kartenberg is Calenberg, a section of the city of Hannover. Also to support the claim, Hinsch, not being a popular name in numbers, the 1942 Hannover City directory listed the following Hinsch:
Amely, Dorothea, and Kathinka, all widows, Hermann, a machinist, and Willi, a saddler.
To muddy the waters, here are some other possible spellings for Hinsch:
Hinsche, Hintsche, Hintz, Hintze, Hintsche, Hinz, Hinze.
Food for thought.
Guenter Loepertz
formerly of Hannover