I found your tree here, and I see that maybe you overlooked the 1915 South Dakota State Census - it lists her maiden name, ["Rep"], and the year they were married - 1886:https://familysearch.org/pal:/MM9.3.1/TH-266-13031-3455-89?c...https://familysearch.org/pal:/MM9.3.1/TH-266-13030-165907-12...
You see on the passenger list for their arrival that they claim they were destined to see "Uncle Christoph Kahn/Hahn/Kuhn" (?) in what appears to say Kulm, ND. I looked it up - yes, there is a very small town called Kulm in ND.
[They claim they were all born in Leipzig, Russia but were German (race). And Elizabeth was blind in left eye.]
So, there's a possible hint - an Uncle with the surname Hahn/Kahn/Kuhn. Now, whose uncle, his or hers? Well, I see you have Sam's mother listed as a Kuhn.
And here might be that Christof Kuehn they were coming to see in Kulm in 1910:https://familysearch.org/pal:/MM9.1.1/MLGN-C9P
BTW - here's where Sophia Wruck died; now you her have her full birthdate (if it's correct) and where born - Kiev (if that's correct):https://familysearch.org/pal:/MM9.3.1/TH-1951-25239-74763-44...
Hope this helps some,