Hi Richard, thanks for your PM. Geez, loved your questions and statements.
1) Mullabrach, was the spelling in the Discharge book. My Google search showed Mullaghbrack in County Armagh and roughly "down the road" from Belfast.
2) Samuel McIlroy born about 1813, this information received in my original research and is open for correction.
3) Reference to Mullaghbrack, see answer number 1.
4) Regarding Samuel's death, as in answer 2, from original research and is open for correction.
5) At the moment, I cannot locate a place of death for Samuel.
6) You raise a valid question as to whether Bartholomew II went back to Sydney or even Ireland. Honestly, I don't know yet. My process of elimination as I get information and certificates dictates my "final" postings! So everything I do, I'm open to correction.
7) Information about William Francis or Harata or her father Hirini, I've only heard "stories". Most relate to William having "issues" with the bottle! Whether that meant any form of abuse, I don't know and my elder cousins aren't or won't say. All that's mentioned is that life for them was tough, considering at the time, they were breaking-in the country for farming. How William got to the East Coast, we have no information on that.
Ohineakai...as you've discovered, it's at the end of McIlroy Road at Waipiro Bay. A track used to lead to Ohineakai, but erosion over the years, means access is via the beach and usually at low tide or you're climbing scrub covered hills and marshy land. The walk from the end of the road is about 40 minutes, the land has a large flat area and an old cemetery with some existing headstones of extended members of the family. Why they moved is not clear, but most of the family moved further up the hills to areas called Taharora and Te Kiekie. Follow your Google map west-ish and you'll find them. BTW, McIlroy Road was named after McIlroy family who lived at the end of the road, Jim McIlroy, a son of William and Harata and brother of my grandmother Mereana.
9) The Catholic Register I mentioned is actually located on CDRom at Auckland Central Library and is a collection of all the Church records, I think for Otahuhu, births, baptisms, confirmations, marriages and deaths. The entry for Henry Arthur shows surname, First names, year of event, the event, fathers name, mothers name and an ID which I couldn't get an explanantion.
I hope this un-muddies the waters a bit.
Chu.