Patrick O'Keefe 1776

Can't go further back than Patrick O'Keefe, born 1776, believed to be from Cork. Married Mary Tobin ( 1765). I have a Passenger Manifest from The Stakesby in 1823, where Patrick comes to Canada, with his oldest son at the time John O'Keefe. they came as part of the Peter Robinson Settlers and made their way to what is now known as the Ottawa area. Believe his name is also on a Plaque at the Rideau River, commemorating those that helped build the canal. His wife Mary and other son Thomas came over in 1825. The original manifest had them listed and then crossed them out. So something happened. But they were able to come to Canada 2 years later. Both Patrick and Mary are buried in St. Michael's Cemetary, Corkery, Ontario. I have been there personally and quite a feeling to stand at a grave with your great ancestor that came to Canada. Looking for any help for prior. I know Patrick and O'Keefe is a very common Irish name !