My grandparents, Samuel Burchell Howard and Bridget Shanahan also homesteaded in O'Neill,Bridget was the daughter of Daniel Shanahan and Margaret HEENAN. The Shanahan's lived in Manitowic County, Wisconsin where Bridget was born.
Did your John Heenan hail from Wisconsin? The Shanahan's came from Tipperaryin the late 1840's.I haven't found much about the Heenans.
Pat O'Brien Samuel Howard began homesteading in O'Neill in 1774. They were married (in Wisconsin) around 1880, had eight kids before moving to Omaha about 1910.Bridget's mother Margaret Heenan seemed to be living with them according to the 1900 census.