Since I posted that question I worked with the Church archives in Bielfeld and got all the info they had. But the records of the Church of the Evangelical parish of Heepen in the years 1766-1779 were destroyed in a fire in the parsonage of Heepen. No documents remain from that period.
I did learn that before 1906-1910, Seiker residents buried their dead in the Heepen church cemetery. Then the village of Seiker opened their own cemetery. But no grave sites exist because in Germany graves are destroyed after 30 years - Manfred Köllner, Bielfeld genealogist.