Kittson profiles and photos from the past and present
The Karstad book indicates that Willie had two siblings. At present I have some evidence for the following:
Brother Edward (born 31 October 1881 Germany; died 27 March 1962 Crookston, MN) wife Millie
Step-brother Carl Oscar Johnson (born 16 May 1875 Germany; died 20 April 1942 Roseau, MN) wife Alice
Step-brother Christian Frank Johnson (born 26 January 1877 Germany; died ?) wife Minnie. His obituary says he also had a sister. She is not included in the Minnesota 1895 census for Stephen where Willie and Edward are listed with father August and step-mother Anna. Perhaps she was grown and married by then or had died.
Any help supporting, refuting, or adding to this is most welcome.