3GGGP John (1811-) & Mary Morrissy nee Murphy ( 1811-?),farmers, from County Cork: provenance and location queries??

Hi!

Im researching my 3GGP  on my maternal grandmother's side,, John and Mary Morrissy , farmers, from Country Cork or Co. Tipperary or Co. Limerick. I only know their names as they appear on the death certificate on one of their children, Mary Robinson nee Morrissy (1838-1907, Mar 20, Armadale, Melbourne, Victoria, Au), my 2GGM.Co. Cork appears on Mary , daughter, death certificate, as her provenance.

Mary left the family farm ,together with her older sister, Catharine Malone nee Morrissy (1833-1880, Wetherstone, Otago, NZ) leaving Southampton aboard 'The Statesman' on July 14 1853, arriving in Hobsons Bay ( Melbourne) on Oct 5 1853, Mary as an indentured dressmaker to Dr Solomon Iffla, Jamaican born doctor who had arrived the previous year at 71 Stephen St, Melbourne,and Catharine as an indentured teacher to Mr John Rendale of the ship "Ajax'.

Family records state that the sisters came from a farm in County Cork, 'a two storey farmhouse with a high stone wall'. The only records I can find is a John Morrissy from Golden , Co. Tipperary, farmer ( 1811-1896) as it fits the same birth date. Nothing as yet for Mary Morrissy, mother. Morrissy or Morrissey are common surnames, aren't they?

My late aunt stated that while staying with her own grandmother,Cecelia Annie Tinsley nee Robinson (1864-1841, Hobart, Tasmania, Australia), the second eldest daughter of Mary Morrissy, daughter, and Daniel Robinson (1809, Londonderrry-1892, Apr 17, Caulfield, Melbourne, Victoria, Australia, Cecelia Annie spoke of a maternal uncle who was provincial head of a seminary in Ireland. Looking at extant records there were around 40 such institutions in the 19 century, so I'm surmising that Fr. x Morrissy's birth date oscillates between 1830 and 1840 so if he became head/ prior , he'd've been around > 40 yo so that'd put it n the late 1870s-1900s. Any tips about how I might narrow the search?.

I also need to locate the parents, John and Mary Murphy's  respective DoB, DoM, & DoD and, most importantly, location of their farm. I can't locate John  in Griffith's Valuations in 1850s nor that of his wife, should she have become a widow before ttheir two daughters left Co. Cork in 1853( improbable). All I know  anecdotally is that the same Cecelia Annie Tinsley nee Robinson, my GGM, allegedly wrote a response to her maternal grandparents around 1880-3 when they asked their daughter, Mary, if the family was being brought up in the old faith to which Cecelia Annie responded that they were  being brought up as CoE as, Mary's husband,  Daniel Robinson ( Ulsterman) was Presbyterian. Apparently, as soon as Cecelia Annie 's mother, Mary Robinson, found out about this letter, she threw her daughter, Ceclia Annie, out of home, when the latter was aged around 16-18. The Morrissys from Co. Cork never wrote any more correspondence to their daughter from then onwards.

How can I locate records for John and Mary as County Cork has hundreds of Townland, Parishes and Baronies?

Cheers,  TM