Thank you very much!
This is the solution of the riddle (according to your hints and the US-Census 1900):
Karl Friedrich Gustav HEHL is born 28 May 1866 in Murrhardt, Germany.
He emigrated to America in 1883.
About 1892 he married Martha Pauline QUAST.
In 1900 he lived as a clergyman in Fayetteville, IL.
1906 he was a pastor in St. Louis, where he died 30 June 1919.
His widow Martha died 21 March 1957 in Madison County.