This is a long shot, but what the heck.I notice that a number of the names which seem common to your families (Paulsen) are also quite common in my grandmother's family line. I have two distant relatives who immigrated to Iowa in the early to mid-1800s, settling somewhere near Davenport.They were brother and sister - Elisabeth Margaretha Paulsen (b. 29 Oct 1847) and Hans Paulsen (b 11 Nov 1823; d. June 1890).According to my data, Hans married a Christine Kroger in the USA.
Elisabeth Margaretha married an Eduard Adolph Ahrens (b. 23 december 1829 in Hamburg) on 23 September 1847 in Albersdorf, Germany.It is not clear whether he also immigrated to the US though my data seems to indicate that he did.Ahrens was the son of a Doctor Andreas Heinrich Ahrens of Hamburg and Margaretha Henriette Deneken.
If any of the above rings any bells, please let me know.Otherwise, good luch in your own quest.