Ugh! You certainly seem to be right on William, son of William and Roxana--that he is not the same person as my William Edson Niles. Ugh!, though thank you for correcting me.
I just cannot seem to locate William Edson Niles. All that I have on him is that he was born in about 1847 in St. Joseph Co., Indiana--this is according to the marriage record in Michigan. It says that his name was "William Edson Niles" and that he was 20 in 1867. (I originally thought it said "Saint Joe, Indiana" and thus thought it was in Dekalb Co., Indiana; but looking at the actual record, which I got off of FamilySearch, it says "Saint Joe. Co., Indiana.") Unfortunately, it does not provide the names of his parents--there isn't a column for that on this one. It states that he was a farmer.
I know they had two daughters, Mattie Viola Niles, born in about 1870, and Rosa M. Niles in about 1872. They appear to have been born in Allegan Co., Michigan--Rosa states so on her marriage record to her husband Ola Cook.
However, by October 21, 1875, William's wife, Olive, married Alfred Cook (1828-1893), and had additional children with him. I don't know exactly what happened to William, though I assumed (yeah I know) that he died, but I have not yet found him on the Michigan Deaths 1867-1897 index. Olive later divorced Alfred and ran off with his son from a prior marriage (yeah, her stepson), Adelbert Cook, and had children with him; so I suppose it is possible that William didn't die between 1872 and 1875, but I'm not sure, though. I have not found another marriage for William Edson Niles, though there is a William E. Niles who married in 1876 an Ida Whitmarsh; but this William E. Niles was born in about 1851 in New York, was living in Muskegon Co., Michigan, and was a lawyer (all according to the marriage record). So, I don't think that was him.