Edmond O'Brien or Edward O'Brien

Looking for family of Edward/Edmond O'Brien who is thought to have been born around 1847 ish  in Ireland.  Ed was married in New Zealand in 1875. His death certificate in New Zealand 1922 gives his parents as Nellie (nee Fitzgerald) and Thomas O'Brien. Some documents have him coming from Limerick but some say Kerry or Cork (as completed by his wife or children).  I'm not sure if he came directly to NZ or via Australia as was commonplace. Family folklore have him being sponsored out here by a NZ sheep station to be a shephard, and he gives his and his father's occupation both as farmer.  We have no reason to think any other family member immigrated to New Zealand with him, although possibly a Michael.  I can not find his immigration/shipping/passenger entry in NZ or Australian records. Edward had 11 children so lots of family names.  The eldest boys being William, Michael, Thomas and Ernest.  Ed's eldest daughters were Mary and Catherine.

The only entries for Thomas and Ellen (Nellie?) O'Brien having children is from Mitchelstown, Cork in the early 1830's when they had Mary, Ellen and Catherine. 

This has been a stone wall for many years.  All suggestion welcome.