Kelly / Dorrian

Hi, my name is Katelyn. 

I'm researching my great-great-great-grandmother and her ancestors. Her name was Margaret Kelly (born abt. 1843 in Drummanus Glebe, Ballintra). Her father was Michael Kelly from the same area. He is dead by 1901 although I think I've found him in the 1857 Griffiths Valuation for the Drummannus Glebe area. She married Hugh Dorrian in 1869 and they had ten kids!

Also living in Drummanus Glebe in the 1901 Census is an Owen Kelly (aged 80) who I believe is an uncle of Margaret although I can't prove it. There is also an Edward Kelly (aged 63) married to a woman named Catherina and living with their kids and his brother John, in that area. Finally, there is another Owen Kelly (aged 60) married to a Mary and living with their kids in the area. I have got the marriage record for Edward and Catherine, his father being John Kelly. I have also got the marriage record for Owen Kelly and Mary, his father too being John Kelly so I think they may be brothers? I'm thinking their John Kelly and my Michael Kelly and the older Owen Kelly, might be brothers?

I'm sorry for the confusion I've probably caused above! :/ I hope you can help me prove the connection. 

You see, I found a marriage record for Edward's daughter Catherine who married a man named James Gildea and on it, the witnes is an Isabella Dorrian, who is my Margaret Kelly's daughter so I definitely think there's a connection - it's just proving it that's the problem! 

I hope you can help, thank you for your time, it's much appreciated.

Katelyn. x