Aandahl/Ondell etc. ancestors

My great-grandmother was Mary Dorothea Ondell (b. 11/5/1855 in Whitewater, Walworth Co., Wisconsin). I am searching for Norwegian ancestors, but have no clues to the origin in Norway. Mary's father was Peter Ondell (b. 1814 - 1819(?) in Norway). I believe her mother's name may have been Mary/Mari also. Mary Dorothea's brothers were Charles (b. 7/28/1851 in Milwaukee, Wisconsin), Lewis (b. 12/15/1852 in Milwaukee, Wisconsin) and Martin (b. 12/9/1857 in Whitewater, Wisconsin). Mary may have been related to Lena Elizabeth Ondell (b. 2/4/1860 in Whitewater, Wisconsin). Lena Ondell was adopted in 1862 when her parents supposedly died. I have 1990 photos of Mary's children at Lena's home in Wisconsin. Both moved separately from Whitewater to the La Crosse/Trempealeau/Monroe county area in the early 1860's. Also possibly are related to other Ondells/Oudells (John, William, Leo, Harry Alice) from Whitewater or Rock Co. Wisconsin. There is also a John Andreas Aandahl that was in the same area in Wisconsin at the same period. May have been the John Ondell that was in Whitewater in 1860. I have extensive information and some 1900 vintage photos of both Ondell families but cannot make any connections. I would appreciate any information or suggestions. P.S. - I also have many, many relatives from Ringebu that immigrated to Barronett, Wisconsin including ancestors and descendents. Richard Schumacher [email hidden]