My Lemmon family lived in Fairbury Nebraska (Jefferson County) area from around 1871-1872. I have not heard of an adoption/guardianship in doing the research. William & Jane Lemmon had children John (born Maine around 1830-1835), Anne, James, Margaret. These children fairly consistently listed with the family on censuses (1850,60,70). There is "another" child William listed on the 1870 (living in Iowa)census born around 1859. This William is not listed on any other census with the family. "Another" child John is listed on the same 1870 census as being born around 1845. (The older child John is married by this time). Again, this is the only census whre he is listed with the family. Once the family came to Nebraska (1880 census), the mother Jane is listed as living with daughter Margaret. Father William presumed dead. Does this help? Last name on 1850&1860 census is Moran. 1870 on censuses last name is Lemons, Lemmon, etc.