I presume you've found Martin, Kate & Lizzie McEvoy on the 1911 census?
Have you seen, on IrishGenealogy.ie, the marriage of George Dixon to Elizabeth Quincey, + baptisms for 3 sons and 4 daughters? The couple moved around quite a bit, as is evident from the baptism info.
I note from the 1901 census that Elizabeth Dixon nee Quincey was born in Wicklow, and if you look on that census, you will see that there is a Richard Quincey, born Wicklow, + family living in Dundrum - a brother, perhaps?
According to familysearch.org, there was also a William Dixon born Dublin 8 December 1876; a child born in Dundrum 2 Oct 1871 (no name/sex), and another child born in the Workhouse, Rathdown 26 Nov 1874.
Good luck with your search!