Is it possible to find the year that Mette was born, the sister of Elling? I have a picture of a tombstone from Norway that has a Mette on it and she married Ole Vangstad and I believe this is the Mette that is the sister to Elling. She lived from 1878-1962 and Ole lived from 1873-1922. You also mentioned that Beret was missing in the 1900 census; that would be because she went to America and lived in the same area as her brother Anders.
Stikleststad in Verdal is a famous place in the history of Norway. King Olav Haraldsson fall in the battle of Stiklestad 1030 against an upraising army of farmers from all over Norway. Olav was later declared holy by the Pope and became St. Olav. St. Olavs College in Northfield Minnesoa is named after him.
Is it possible to find out if Elling had any children? I have some pictures of gravestones from Norway and I think one of them is a daughter of Elling. I believe he had a daughter named Marta born April 10, 1909 and she married Trygve Holmli born Feb. 4, 1901.
Can´t find neither Elling´s wedding record or any children born in Stiklestad 1900-1917, but he might have moved to another parish (temporary) or I might have overlooked him.