Mike,
The 1901 census lists another child to William & Rose Ann. There was a Sarah Ann born 29.7.1900:
https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_retur…
1901 census:
http://www.census.nationalarchives.ie/pages/1901/Antrim/Ballymoney/Kilraughts/944764/
She died in 1903:
https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_retu…
Martha was born in Killyrammer in 1902:
https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_retur…
Family in 1911:
http://www.census.nationalarchives.ie/pages/1911/Antrim/Ballycregagh/Kingarriff/128767/
All the various births death and censuses are at different addresses. That was fairly common. Labourers moved around all the time according to the available work. The house numbers don’t relate to any number the property might have today. They were just the enumerator’s private numbering system which varied from census to census. It was just their way of ensuring every hosue was counted. In rural areas in those days, and until quite recently, your name and your townland was all that was required to identify you. The postman and anyone else who mattered knew where you lived.
William’s age shoots up between the 1901 & 1911 census. That was normal too. The old age pension was introduced in 1909. To qualify you had to be 70 or older. Folk knew the authorities sometimes used census records to verify age and consequently many folk put on quite a few years in 1911 just to be on the safe side. (William said he was 25 in 1886, so born c 1851). Ages need to be taken with a pinch of salt in records in Ireland in the 1800s.
Possible death for William 7.1.1931 aged 75. Rose 11.12.1930 aged 65. Both registered in Ballymoney. You can view the original certificates on-line on the GRONI website, using the “search registrations” option:
https://geni.nidirect.gov.uk
You will need to open an account and buy some credits. It costs £2.50 (sterling) to a view a certificate.
What else are you trying to find out?