Although there is probably no obvious direct connection between your August Zabel and my grandmother, Ernestine Zabel, I have found from searching another family surname that after some research we did find a family link.
Because Zabel is not a common name we might be able to find some commonality.
My grandmother, Ernestine, immigrated to the USA about 1890.I know for certain that she was born in Tarnowke and that she had a brother named August.Although your August might not be my grandmother's brother, they might have been second cousins.
Have you been able to get any information about the family in Germany?It is difficult if your ancestors were from the part of Prussia that is now Poland.
I do know that my grandmother was a Lutheran but I do not know if there are any church records because of the area being in the Russian sector of East Germany before the Berlin Wall came down when the area was ceded to Poland.
Where about in the USA did the Zabels settle?My grandmother lived first in Wisconsin and then Chicago, where she married my grandfather.There are some family photos of some relatives in St. Louis.