William and Mary Wall

Good morning. I am researching my GG grandfather James Wall the son of William and Mary Wall who arrived in Boston, MA, USA in 1850 as a famine immigrant. The only records I could find show that he was a minor when he arrived and I cannot find records for any adult with the same surname who might have accompanied him. I believe a family of cousins with a son named James arrived around the same time but DNA results show that they were not the children of my William Wall. They were probably the children of William's brother.

On his naturalization papers James states that he came from County Kilkenny. So far I can find only one William and Mary (Farrell) Wall who had a son names James born around 1830-1835. I am not convinced that this is the correct family as they are shown as farmers. My James arrived as a shoemaker. Additionally the names of their other  children do not appear anywhere in my family tree. In summary, my James Wall states on his marriage record that Mary and William were his parents. He named his children Francis H., Benjamin J., Robert Emmett, Loretta M, Frederick Leonard and Joseph. His cousin is Garrett Wall and Garrett's father's name is Patrick.  I have used roots.ie and built a spreadsheet of all the potential Kilkenny couples named Wall and cannot find a match in which I am confident. I have also searched MYHeritage, Ancestry, Familysearch, and Genealogybank. Have you any suggestions for where else I might look? Is it possible he lived in a county other than Kilkenny? Have county boundaries changed since 1850?

Many thanks. Alice