The Dörrs who went to Wisconsin were descendants of "Johann", not "Fred," Dörr and Justine BETHKE (note spelling), according to Friedheim Evangelical church records (Wirsitz County, Posen). Son Christoph's full name was "Wilhelm Christoph".
There is a Johann Michael Dörr b 2 June 1828 at Zelgniewo to parents Christoph Dörre and Rosina Kewit, but there is also a Johann Michael born 5 Oct 1832 at Schmilowo to parents Christoph Dörr and Henriette Schultz. I'm not sure at this point which one is "Johann", but hopefully in a couple weeks I'll know more when I see the film again.
If anyone wants the Dörr family as more fully listed in the Friedheim records, let me know (back to Stephan, father of Stephan Dörr (b ca 1768)).
All the best, Ken Neumann