ok here is what I have, which is mostly gathered from census records and online indexes...
Isaac Tawney [Birth date:24 February 1849
Place: Fort Wayne, Allen, IN] married Ida Porath 17 October 1893 Ironwood, Gogebic, Michigan. I am assuming at this point that his previous wife,Isabella (JONES) Tawney, died prior to that date. I have other sources that indicate she died prior to 1900, but have not been able to locate anything more specific so far. I also have not been able ro come up with any further information on the children David, John, and Margaret.
I had not found the information that said Isaac died in a fire. Is there a chance that the entire family did as well? I would be interested to hear more about this or anything else you may have to share. I mostly have information on Isabella's family (siblings and parents)--and it has been difficult and slow going to find out very much about them.