I have some of the LDS microfilms of the Ev. Kirche Levern on loan at my
local Family History Center. The Levern churchbook includes Sundern.
Perhaps I can help with some lookups.
My wife's Niemeier ancestors were from Levern. Other names of interest in
the area are:
Bohn
Brinkemeyer
Klosterman
Mösemeyer
Tahnen
Tegeler
Edgar Dohmann
edgar@dohmann.com