Hi I think I found the grave of your William and Rose McDaid in Derry city cemetery via find a grave.com My late father Brendan McDaid's sister Roisin, who died as a baby, is buried with them along with their son William McDaid. My grandfather was Charles Gerard (Gerry) McDaid, born 1912 and pictured, from Beechwood Street in Derry and I think his parents were James McDaid and Catherine Boyle going by the 1911 census. I've hit a bit of a dead end since then though and this is the only link I can find to my grandfather Gerry's ancestors. Trying to work out the connection between William and Rose and my grandfather Gerry's father James McDaid.
https://www.findagrave.com/memorial/205492765/william-mcdaid
