Hi, Nikki. Nice to hear from another McDaid cousin! The tombstone photos you found online were taken by me and another cousin. I was in Ireland a few years ago and managed to locate the cemetery. It hasn't been used since the 1950s so is a bit isolated and hard to find unless you know exactly where to look.
I'm in touch with several cousins and there is no information on Joseph or Sarah's parentage that any of us have found. The majority of Ireland's older records were burned in a fire back in the 1920s so it's very difficult to locate information before the 1900s. What we have found is that our McDaids were most likely Presbyterian, which means they probably immigrated from Scotland at some point. I've moved my research for Joseph to Scotland but haven't found anything else yet. We still don't know Sarah's maiden name so unless we find that, we're at a brick wall with her.
From John McDaid's will, we do know that Alexander was the only one to immigrate to the states and the only one of the siblings to marry and have children. I have photos of Alex, John (his twin), Mary Jane and Ann. Feel free to email me at firstname.lastname@example.org
if you'd like copies. When you email me, please include which of Alexander's children you descend from because I have info on all of them.
I uploaded these McDaid cemetery photos a few years ago so feel free to copy and save them to your computer if you haven't already. http://www.genealogy.com/users/d/a/v/D-r-Davis-/PHOTO/0045ph...http://www.genealogy.com/users/d/a/v/D-r-Davis-/PHOTO/0046ph...