Mulleen family

I am trying to find out where my g, g, grandparents are buried.  They are John and Catherine Mulleen,(maiden name is Prendeville or Prenderville)..

They were born in Ireland, John was born in 1831, Catherine was born in 1835.  They were married December 19, 1851, in Fermoy, Cork, Ireland. There immigration date on the 1910 census is 1868.

I found them on census records in Canada for the year 1871, they lived in  Cataraqui, Kingston, Ontario, Canada.

Catherine died December 28, 1882, her body was placed in the vault of St. Mary's Cemetery for spring burial, however they have no record of her being buried.  I can't find out when John died, he was alive in 1871 (according to census) on the 1881 census Catherine is listed as a widow.

They had 2 children born in Ireland, Thomas and Margaret, and 3 more children born in Ontario, Canada, Edward (b.1868)  William(b. 1870) John (b. 1866)

Hoping there is someone out there that knows something about this family.

Thanks to anyone who responds.