None of the people I mentioned are buried at Potters Field, but I would be interested in any information you find in the course of your research on the three people I mentioned, should you discover anything.
I'll provide a little more detail than I did earlier.
Berit Andersdatter Moen, aka Betsey Olson, aka Elizabeth Maria Olson, aka Betsey Anderson. Born 30 Nov 1850 in Målselv, Troms, Norway. Institutionalized at least from 1900-1920, as she is enumerated in the census for the asylum in 1900, 1905, 1910, and 1920. She could have been in the asylum as early as the 1880s, which would mean she lived there for the last 30-35 years of her life. She died 24 Dec 1920. Buried Evergreen in Menomonie.
John Olsen Moen, aka John Olson, aka John Moen. Born 6 Feb 1830 in Målselv, Troms, Norway. He is listed on p. 28 of the 1915 annual report for the asylum in the physician's section where he is reported as one of the deaths, the cause of which was old age. (The Colfax Messenger reports that it was following a bad fall.) He died 25 May 1915. He is buried at Evergreen in Colfax.
Martin Nelson or Nilson. Born 26 Jan 1846 in Norway. He is enumerated as a resident of the asylum in the 1905 where he is listed as a farm laborer in the section before the inmates are listed on sheet 10 (or page 355). He died on 2 Oct 1916 and is buried at Evergreen in Menomonie.