I am also searching for information on the Hacker line in the New Ulm, MN area.
Would you happen to have a Maria (Mary) C. Hacker (b. 1842 Bavaria, d. 1910 New Ulm) in your line? She married Clemens Hoffman in Germany and arrived in the USA abt 1884. Their children were: Cresentia, Mary, Max, Frances, Theresa, Joseph Herman, Wolfgang (my great grandfather), and Clara.