According to his gravestone his full name was Frederic Errel Arthur Wynnemer:
Minnesota Death Index, 1908-2002 Name: Frederic Errel Arthur Wynnemer Death Date: 21 Apr 1949 Death County: Waseca State File Number: 017114 Certificate Number: 017114 Certificate Year: 1949 Record Number: 1093583
Minnesota Cemetery Inscription Index, Select Counties about Frederick Wynnemer Township:Woodville County:Waseca Name:Frederick Wynnemer Birth Date:1867 Death Date:1949 Cemetery:Woodville Comments:VET. CO K 12 MN INF SP. AM. WAR. SP. ROSE HOLTZ. WITH MILDRED, ROBERT L. & MARJORIE G Section:I
In the 1900 census he listed age 32, birth month and year June 1867
In 1910 he again listed age 32, in 1920 age 42, and in 1930 age 62
In both 1900 and 1930 censuses he listed 1876 year of immigration (not listed 1910-1920)
If he came that young, it must have been with his parents or other relatives.