Michael and Daniel McMullin / McMillan were indeed twin sons of Angus
McMullin / McMillan and his wife Ann MacDonald. Family correspondence shows
that both Mike and Dan moved to California after marrying in Cape Breton
and, although there is no indication as to who they married, it is said that
Mike had a family of ten, and Dan four. Both appear in the family home in
the 1881 Census, so they must have married after that. Lynn's information
that these twin brothers married members of the wider Cusack family goes a
long way - for me, anyway - to explaining why connections between McMillans
and Cusacks were still remembered in Sydney nearly a century later.
The Flora who appears at 19 years of age in the 1871 census is the same
Flora that married William Cusack. Regarding mother Ann's name, I guess
that she was known by the diminutive "Annie" among the family.
Lynn - If you could send me the obit for Francis Cusack McMillan as you
offered I would very much appreciate that.