BLM land records has an Ole M Olson picking up land in 1897. It was Fortier Township, western half of section 30. No close cemeteries. They are so close to South Dakota that they might be buried over there. I do not have a listing of SD cemeteries. There is a Bohemiam cemetery in Lincoln county but I do not see an Olson ending up there.
They also have a Hans Peterson picking up land in section 10 in Normania township. That was in 1877. Spring Creek and Bethelhem cemeteries are close to that one.
The local historical society should have cemetery transcriptions. They are located in Granite Falls, MN. Considering when they died, their graves should be marked.