Re: William & Minnie Ernst - Iowa
There was an Anthony Ernst who married (20 Oct 1861) Margaretta Wieneke (b. June 25, 1839;d. 28 Aug 1918). They had the following children: Mary Magdalena, Anthony, Anna, Mary, Amelia, Joseph and August. The Wienekes were from that part of Iowa, Clinton or Fairfax, I think.
See the my postings on the Wieneke Family Genealogy Forum, "Wieneke Reunion, 1927, Pt. 1-3", for mention of Ernst family members who attended.
I also have letters from Wieneke relatives who mention their Ernst cousins.
Contact me if you think these are relatives of your Ernsts.