I believe it's 2 Old Lisburn Street - but I cheated just a little... the writing on the civil marriage is messy, the first word looks like it has 4 letters, the second word looks like it starts with Lis... so to cross check I had a look at the church marriage (2nd last entry on the page), and luckily the priest, a J. Brady has nice neat handwriting and reasonably clear 2 Lisburn St. See the c1890 OSI Map
Thom's 1894 lists a Lisburn Street, and a New Lisburn streets, so think the civil registrar used 'Old Lisburn street' was to differentiate between the two. Both are 'northside' so across the Liffey from the church. The Old & New streets were adjacent with Old Lisburn Street running between Coleraine Street and Lurgan Street, and New Lisburn street continuing to the west as far as Upper Church Street. Just the 'Old' Section of the street remains today.
The 1894 listing for Old Lisburn Street shows the following.
1. North City Dispensary
2 to 5 tenements
6-8 Linen Hall Barracks
the listing for New Lisburn Street for ref.
1. M. McGrane, undertaker , hearse & coach prop.
2 to 4 tenements
... Church Street...
5. Philip Brady, grocer
6. James Dunne, provision dealer
Agree with the bride's addess, although think it'[s place rather than street. There were at least three streets named Fitzwilliam place at the time...
Fitzwilliam place, Fitzwilliam square
Fitzwilliam place, north, Stanhope street
Fitzwilliam place, Fitzwilliam lane
the second one is in the north of the city, so unlikely for a marriage in St. Andrew's. I think the third is the best candidate in this case - it's shown as Little Fitzwilliam place on the c1890 OSI and also on current maps. Like many small lanes and streets, details for Fitzwilliam Place, Little are not shown in Thom's Street listings, although it is mentioned in the street index.
EDIT : apologies Kaye for overlapping - didn't see your post...