Rice Family

I am searching for confirmation that my ancestors originated from Cavan, specifically Knockbride. Through DNA matching, I have confirmed that I am a match to a James Rice (actually to one of his descendants) that was born in 1810/1811 in Cavan, married Elizabeth Murphy (from new York), had a number of children two of whom were John (born 1848/49 and Agnes born circa 1840. The family moved to Canada in 1850 and has remained there. I have several Canadian documents that demonstrate that my DNA match is a direct descendant of James, John, and Agnes and those documents indicate that all were born in Cavan. I also have an ancestor named James Rice, born between 1818 and 1828 (most likely closer to 1828). He immigrated to the US in the 1840's and settled in Waterford, Connecticut, where all of us Rice's (his descendants) have lived ever since.I can not determine where in Ireland he came from and to what line of Rice's he belongs. There was some beliedf it was Down but I have no data to support that. His death certificate says his father was a Barney Rice (Bernard/Barnett, etc). My research discovered that there was a Barnett Rice that lived in Cavan and who had a son James born in 1828. A Bernard Rice (perhaps Barnett and Bernard are the same person) lived in Cavan from 1792 to his death in 1877. This information is consistant with this being my ancestor but I would like to confirm it somehow. The fact that my DNA match also comes from Cavan lends more support to that. As such, I would like to find out if there is a connection between that Barnett Rice  and the James Rice of 1811. What is Barnett/Bernard's father's name and is it my ancestral line. Any help in making this determination would be super.