Ancestry

There's a possible match for John's baptism but in Wexford town in 1863 rather than Enniscorthy, about 25km apart (~15 miles). Parents names match the details  you have, and ages reported later are often inaccurate, so being a couple of years eaither way is not a problem. The names are reasonably common, so there's a small possibility that this is a different couple.

You can view the register on the National Library website - John's baptism is 3rd from the bottom of the left page.

I'll have a look and see if I can find any other children...
 

There's a baptism of a Mary Furlong in Enniscorthy parish on the 7th Sept. 1859, same parents names as those you mentioned - see the 2nd entry of the left page   I dont see other children baptised this this couple in Enniscorthy parish but there is a promising marriage for James and Eliza in the parish in 1858 - see the 17th November on the right page , note parts of this register are not in date order.  Early marriage records dont include much detail just the date, names of the bride & groom, the celebrant and the witnesses - an Ellen Lynch & Catherine Lanton[?]