Amy, I read your post and thought I would add that Rosa was first married in Minnesota to John's younger brother, Joseph Davis. They had 3 children and then Joseph died of pneumonia at a young age in 1900. In those days I believe it was not unusual for a bachelor brother to assume responsibilities of the deceased brother's family. Therefore, the 3 oldest children were John's nieces and nephews as well as his step children!
So this explains the three oldest children and their relationship to John.
I'd like to thank John's granddaughter for contribution to this project. I couldn't have told his story so well with out her. Don't worry though. There will be more on the way. I can tell he was a very interesting man, and we are still working on getting his picture on here too.