This is a project to find the ancestors of Ernst J. Lehmann and his "cousin" (?) Johanna Lehmann Harder. EJ Lehmann was the founder of the Fair store in Chicago in 1875. He was born in 1840 in Germany and immigrated to the US with his family when he was 2. His wife invited his cousin Johanna and her husband Frederike Harder to come to Chicago and work for the Lehmann Estate.
I'm having trouble figuring out how these two "cousins" were related.