Helen is with her family in 1910 census
Source Citation: Year: 1910; Census Place: Baker, Kingsbury, South Dakota; Roll: T624_1483; Page: 13B; Enumeration District: 0256; FHL microfilm: 1375496.
Thomas her dad is with his third wife Martha (Her mom). Thomas and Martha have been married 11 years. They moved to S.D. bet 1906-1907.
Russell is with grandparents in 1930
Source Citation: Year: 1930; Census Place: Renville, Bottineau, North Dakota; Roll: 1732; Page: 2A; Enumeration District: 0040; Image: 228.0; FHL microfilm: 2341466.
Have you found Russell's birth certificate? It is odd that she would name the father if they weren't married. I can't find anyone in 1920. You might try tracing the other family members to see if they know anything.