I have found that Sarah Brandt was the incorrect name for Augusta and Edna's mother. On their marriage license John M. Allender's bride was Sarah Boroughs. I still haven't found out when Sarah died but it must have been between 1875 snd 1880.
I went to Union Co. but death records/birth records don't go back that far.
I have found out a lot about John M. Allender from the military records and saw his burial place at the National Military cemetery in Dayton, OH. You can see it on Findagrave.com.
Have you found out anything else about Edna's origins?