All very interesting - thank you.
I found the "Blodora" family you referred to in the 1870 Dodge county census. Using those names and some well-placed wildcards I found a ship passenger record that lists Caroline, born 1827; Anna, b. 1851; Minna, b. 1863; and George, b. 1864. The record also lists an Emilie, b. 1848, and Elise, b. 1854.
Search the New York passenger lists for:
Arrival Date: 25 Oct 1869
Port of Departure: Copenhagen, Denmark and Swinemunde, Germany
Place of Origin: Stettin
Ship Name: Fulton
Alas, no mention of William and Herman…