Conclusion and Next Steps
I set out researching the Fehrmanns of Cincinnati because I was trying to track my gr-gr-grandmother's family back to Europe. Johanna was said to have a father Louis Fehrmann, but as I worked on collecting information abou this family, I got increasingly confused by the number of Fehrmanns, the numerous name changes, and the drifting around from address to address in Cincinnati. So I decided to track them all, because I beleived sooner or later I could show they were all relatives anyway.
I did not know her mother's maiden name. If I could be sure of her parents' names, and find a location in Germany where they were likely married, I could continue my research in Germany.
I think I've shown that Johanna is not a daughter of Louis Fehrmann, but instead a daughter of a Kuester, her mother's first husband.
A good place to find crucial information on her father is most likely the church records, where I expect I'll find death, confirmation, and baptism records relating to Johanna, her natural father, and Louis Fehrmann's first wife. Civil marriage and death records, cemetery records and city directory information should provide a lot of information on the Kuester family.
Of course, it's an intriguing twist that Hanna married a James Kiester, for whom I've found little information other than he was apparently a railroad worker. I suspect the possiblity is good that by researching the Kuesters, I'll encounter James.