Oestreich - Wisconsin, Iowa, Minnesota

Looking for information regarding my gggrandfather, Amil A Oestreich.I believe he was born in Wisconsin in abt 1867.He lived in Concord, Jefferson, Wisconsin in 1870 according to census records.He married Georgia Snow in abt 1897.Per census he was living in Iowa from about 1885 to at least 1910.In 1920 lived in Minnesota.In 1930 lived in South Dakota.Was a minister.Moved back to Iowa for retirement which is where he died in 1950.According to his obituary, his father was Henry Oestreich.My ggrandmother was Florence Oestreich, dgtr of Amil & Georgia (possibly not biological).I also have a picture with the name Gladys Oestreich but have been unable to figure out how she ties into the family.Any further family information would be greatly appreciated as this is all I have been able to gather.Thanks so much.
Jessica