Hi! My name is Matt Eikamp. I believe that of those you listed, I would be a descendant of Jacob. That is, if Jacob is the same Jacob Eikamp whose son Fred was born in 1889 and spent time living around/near Britton, SD. Fred's son, Fred B. Eikamp, was my grandfather.
I was having trouble finding names of my ancestors beyond the names of my great-grandparents. Nice to see this message.