John Fitzgerald and Johanna Brosnihan/Brosnahan/Brusnihan

This is a bit of a fishing expedition! I am trying to locate husband and wife John Fitzgerald and Johanna Brosnehan who emigrated separately to New Zealand - he in 1857 and she in 1861. The only records to come to light so far that have this combination of names in Kerry in the right time period are two birth records in Ardfert which may be for their children... Patrick Fitzgerald, baptised 3 April 1844, son of John Fitzgerald and Hannah Brosnohan, witnessed by Patrick Brosnahan and Brigid (looks like) Mahony; and Ellen Fitzgerald, baptised 2 January 1842, daughter of John Fitzgerald and Hannah Brusnihan. The thing is - the only children that joined them in New Zealand were John (born c1839, Kerry), Elizabeth (born c1841), and (possibly) Dennis (born c1843) - I say 'possibly' as he could be a nephew, but I suspect he was their son. Johanna's parents were definitely John and Mary Brosnehan (from her death cert) and she was born c1820, in Kerry. My Fitzgerald family were a little further south, near Tralee, by the early 1850s (Gortagullane/Arabela townlands...Griffith's valuations). Then they were part of 3 or 4 distinct waves of Kerry Irish to emigrate and settle in the areas at the top of the South Island of New Zealand. Hopefully there is someone out there who might be able to confirm that this is the same family I have stumbled across in the Ardfert records. I haven't located baptism records anywhere for John, Elizabeth and Dennis Fitzgerald nor death records for Patrick and Ellen. Neither have I found a marriage record for John and Johanna nor their daughter Elizabeth Fitzgerald who married John Dennis Moran c1859 in Ireland. Elizabeth and Dennis Moran emigrated with their two small children Mary and Ellen along with Johanna and Dennis Fitzgerald in 1861 joining the patriarch of the family John Fitzgerald and his eldest son John who had emigrated in 1857 and 1859 respectively. As an aside .... if only the Fitzgeralds and the Morans had known about growing grapes ... the land they worked in Marlborough, NZ was ideal for this and blimmin' hard work for farming! Thanks for reading.