Morgan,
The addresses (residence) where the families lived were Taylorstown and Moboy respectively. Your townland was all that was needed to identify you in rural Ireland until the 1960s. The postman and anyone else who mattered knew where within the townland that each family lived. No further information was required to identify you or get a letter delivered.
I think this is David McCammon, siblings and their mother in 1911:
http://www.census.nationalarchives.ie/pages/1911/Antrim/Portglenone/Kilcurry/124160/
and the family earlier in 1901:
http://www.census.nationalarchives.ie/pages/1901/Antrim/Portglanone/Kilcurry/940868/
Note that they had 5 children, one of whom was dead by 1911. (There were only 4 in the 1901 census, so I suspect the 5th child had died before that year).
Christian Brethren is what many people call Plymouth Brethren. (Though Brethren don't particularly like that terminology).
David wasn?t born in Glasgow according to this census, but his brother John and sister Jane were, so perhaps there?s a mix up? Should be easy enough to find the birth certificates if you want to. Let me know if you need help doing that.
As you said, the family evidently went back and forth to Scotland in the 1880s. The family (or at least the mother) were apparently in Scotland c 1881 when E Jane was born, Ireland in 1882 for Agnes birth, Ireland 1884 for David?s birth, Scotland c 1886 for John?s birth. You might therefore want to check the Scottish censuses for 1881 & 1891 in case the family shows in either of those. (The equivalent Irish censuses have been destroyed).
The revelation records show that John McCammon moved to Taylorstown in 1914 where he was renting plot 7bca. His name was still against that property in 1929 when that set of records finishes. Presumably his son David moved to Skerry parish when he married, to set up his own home, if his daughter was born there in 1922
I can explain how to find plot 7bca, should you ever wish to visit it. To find exactly where David and Mary lived, I?d really need the townland from Agnes birth certificate. Do you have a copy? If not, you can plough through all the revaluation records and find it that way. There?s about 40 townlands in Skerry, so it would be a bit of a plod.
http://www.proni.gov.uk/index/search_the_archives/val12b.htm
There's a will in PRONI for John McCammon. Here's the abstract (summary). The will itself is not on-line. You would either need to pay PRONI to send you a copy, or get someone to call and get a copy.
Full Abstract : McCammon John of Taylorstown county Antrim farmer died 19 September 1933 Probate Belfast 8 March to William Law farmer. Effects ?15.
Elwyn