29th & 30th are Wednesday & Thursday. I don't know of any singing sessions on those nights. There are tunes sessions on Thursday in Hughes Pub and also the Chancery Inn which is near by. The Chancery now has a different name up on the door. I think it might be O Reilly's but I'm not sure.
I don't know much about Wednesday night sessions in Dublin City Centre because I play at a local session in Raheny GAA club on a Wednesday night. There'd be some singing there if she was interested. However it might be a little bit awkward getting there and back if her accommodation is in the City centre - its about 5 miles out of town and Public transport finishes before the session does. Taxis are an option, but they can be a bit hard to come by and very expensive.
If staying in town Hughes and the Cobblestone are both worth checking out on Wednesday as well.