I am sorry to say I have no record of your Mary Kelm married to James Owen Nicholson. I have a rather complete genealogy of Emil's descendants, but it does not have his siblings nor parents. In your records you have John Franklin Nicholson born in Quincy, Illinois which is about 200 miles south-west of Chicago in Illinois, not exactly a suburb.
Good luck, let me know if you find Mary's parents. I will keep her in mind in my searches.