I talked about John Cooper's kids here - they just seem to be a bit of a mess generally. I recently ran across this article regarding Aaron before he left Stephenson and Winnebago Counties, Illinois for /Butler/Bremer County and later Franklin County, Iowa.
The divorce of Anna Blaser from Aaron took place in 1904 in Butler County.
This may well have had something to do with the sale of property in 1904 and early 1905
He died in 1920, having never married again.