The 1901 census for Ireland had 77 individuals with the first name of Callaghan.Probably 65 of the 77 were in Co. Cork. Good number were McCarthys. Also found a father and son both named Callaghan Callaghan.
Regarding your main question, the two abbreviations on the screen shots were likely for Callaghan. There is a good possibility that the same person married twice but no way to verify. I did find on the subscription site Roots Ireland a baptismal record for a Catherine Halloran father Callaghan and mother Mary Buckley
Catherine Halloran baptized March 1 1812 in Killavullen/Annakissy parish father Callaghan Halloran mother Mary Buckley
No other children to that couple.