The 1854 marriage was in St Anne's Belfast (Church of Ireland). Tradition was to marry in the bride's church. So she was probably C of I. Her address was Templepatrick (a parish about 10 miles outside Belfast). Her father Edward was a stonemason. Templepatrick's church of Ireland records start in 1827. Mary Ann was 19in 1854 so it may contain her baptism and that of any siblings. There's a copy in PRONI (the public record office) in Belfast. Statutory birth registration started in Ireland in 1864. I found the birth of one male child on 3rd Nov 1866 at 50 Stanhope St, Belfast. Father's occupation builder. The child had not been given a name at the time the birth was registered. (That was common then). So the family were still in Ireland in November 1866.
The groom's address on the 1854 marriage certificate is just Belfast. His occupation Carpenter. His father was Samuel Hunter, farmer, so that suggests he originated outside Belfast. (You don't get too many farmers in the middle of a city). Possibly he came from Templepatrick too. It might be worth checking the same Templepatrick church records. Griffiths Valuation for 1862 does list a Samuel Hunter farming in Templepatrick. That could be William's father. Worth checking the Presbyterian records too in case he was that denomination. They are also in PRONI.