Spent quite a while last night searching for more details (using only first names, etc. in several databases) without finding what I was looking for but then with a fresh start this morning
might have found a clue!
There’s probably 2 ways this can work- if the family were Macks from Coleraine or McKays from Westmeath. However, it's not as easy as putting everything together in one nice, neat tree, as you know. One problem, of many, is Kathleen born 1871 in Coleraine but mother Mary Mulvey dying then in Westmeath. So,
Mack, Coleraine
1) no birth registrations or R.C. baptisms found (searched church records 1869-1873). Extracted Irish births (1864-c1881) not complete but has good coverage yet none of the children from either marriage seem to be listed
McKay, Westmeath (online trees)
1) Westmeath given as birth & death place of Mary Mulvey, marriage of William Mack to Elizabeth Shaw, birthplace of daughter Susan Anne McKay in 1876
2) “North Coleraine” and Westmeath given as death place of Mary Mulvey
3) William McKay’s mother supposed to be Rose Farmer & William Mack had daughter Rose. Trees list McKay children as Rose & Kathleen with details matching those of Rose & Kathleen Mack
4) Londonderry & Derry given as birthplace of children Annie Jane & Elizabeth McKay (1879,1883)
Now, if ‘Coleraine’ is correct then there are a few other possibilities. 'North Coleraine' doesn't really fit the Londonderry one. The search has concentrated on Coleraine, Co. Londonderry but there are 2 other Coleraines in Ireland.
1) South Tipperary (east of Cashel)- Cashel PLU, Magorban civil parish
2) King’s (Offaly) (northwest of Tullamore)- Tullamore PLU, Durrow civil parish.
Less than 2 miles from Westmeath borderSince the family were R.C. is might be worth checking the online Parish Registers to see if any baptisms or marriages can be found.
http://registers.nli.ie/#home_mapP.S. while looking at Australian records I came across a death for William Mack (1920 Windsor NSW)- have you seen this or ruled him out as another child of William and Mary?