Looking for O'Briens

This is kind of complicated but here goes. I am trying to somehow figure out how James, Michael, Patrick and John O'Brien fit together. Mary O'Brien-Daughter of Patrick and Margaret came and was married in Minnesota to Michael Balfe in 1886. She as the Belle Plain Herald says was a Niece of Michael O'Brien of Assumption Township in Minnesota. Her Mother and Father are Patrick and Margaret O'Brien whose Fathers were James and John. That being said my Great Grandmother Lizzie O'Brien who came to Minnesota in 1880 called Michael O'Brien UNCLE in each of the Letters I have-Michael died in his home in 1903 and about the age of 80-83. My Great-Great grandfather died in 1907 at about the age of 80-85 years old making me believe they are brothers. If Mary O'Brien Balfe was a niece to Michael O'Brien its either through James or John O'Brien whose ages I haven't found yet or they are siblings of Margaret or Patrick O'Brien in which case I go back one more generation. I don't know who My Greatgrandfathers parents were and if I did it might put a bunch of people in place. There also is a James O'Brien (about 1836-1915)a bachelor, who lived in Tomhaggard Co Wexford. After Patrick and Margaret's daughter Alice's husband died she moved in with him and she was known as "HIS NIECE". She also inherited this property on his death. Her daughter Elisabeth inherited the house and she married a man named Brady and as they had issues with children they never had any. OK--Try this one-- Patrick O'Brien's(my greatgreatgrandfather) had James O'Brien who had Michael O'Brien who had Alice O'Brien in 1953. Alice's mother had some issues along with 14 children and Alice went to live as an infant with Elisabeth Brady and Alice inherited the house-because of this fact I know that that these family's are definitely connected but exactly how we don't know. I told you it was complicated !!