There were two Luloff (Iowa spelling) families that settled in Sheboygan and Manitowoc counties, near each other in late 1840's or very early 1850's. Frederick Lulloff (abt 1790-d. bef. 1870) and wife Dorthea Sophia Lorentz and Michael Lulloff (1796-1864) and wife Anna Sophia Lorenz. There is a strong possibility that these couples were brothers and sisters.
We have John Luloff (b. abt. 1820 - 1897, son of Michael & Sophia) who was grown when his parents came to Wisconsin. He remained in Germany and came at a later date - late 1860's possibly after the death of his wife, Henrietta Meyer/Meier. He went to Clark Co. by 1880 while his older children went to Iowa. It is a possibility that he could have had a son that has escaped all those researching these families.
Herman Gosse (b. 1854) husband of Mary Loos was a grandson of Frederick and Dorothea Sophia (Lorentz)Lulloff. Several children/grandchildren of Martin and Charlotte (Linde) Gosse married children/grandchildren of both Lulloff couples. The younger couples settled primarily in Clark County, Wisconsin and Buchanan County, Iowa. As mentioned in previous response there are a number Loos families in Clark County and area.