1870 census: Arnold James, 46, farmer, 500, 100 - Margaret, 36, keeping house - James F?, 20 - Etta J, looks like 6, could possibly be 5 - Willie A, 3 All bps Maine.
Etta J. Arnold married Orren H. Soper July 29 1879 in Salem, Franklin, Massachusetts.
1920 census,Boston, Suffolk, MA: Soper Leslie, head, renting, 37, Maine 3x, painter - Anna, wife, 30, MA, Ireland, MA - Dorothy, daughter, 5 - Herbet?, son, 4 5/12 - Barbara, daughter, 2 6/12 - Violet, daughter, 3/12 - Daisy, daughter, 3/12 - Davis, brother, 38, Maine 3x, no occupation All children born in MA. Living at 21 East Canton street. Enumerated 1/3/1920.
Finding the birth records for Leslie or David Soper could help a lot. Familysearch has a lot of Maine records online. If you go into Maine, Vital Records, 1670-1907, then Vital records prior to 1892 you may find your families. It's only indexed after 1892 but you can just browse through the images before that.