Hi, for this family mother was Catherine, Patrick's birth registered 1883 Buncranna CP, father John, mother Catherine, Bridget 1884 same details and Rose 1886 again same details, looks like Ellen's mother was Catherine McLaughlin
This couple John McDaid = Catherine McLaughlin married in 1873 page Vol 17 page 131 of the civil register, Buncranna, Catherine's father was John McLaughlin, Johns father was Owen McDaid
Regards