Don't drive in Dublin whatever you do. My cousin has been rear-ended twice by people texting and driving, it's commonplace and very dangerous.
Plus the drinking/driving thing is very much a reality there as well.
Highly recommend the Camden Court Hotel. It's central, family friendly and has a great pool and rec centre attached.
You can walk to just about anywhere, take the LUAS (tram) or DART (rapid transit train) or the bus.
Taxis are ok for short trips as well.
If you're flying in and will be fatigued, I'd be very wary of jumping in a car right away as you have to get used to right-hand drive on a stick shift. (I've heard that the rental cars aren't automatics.)
The Guinness tour is interesting, vast warehouse space, lots of "inner workings" type displays, but it's really all about the free pint at the end in the rooftop bar.
Check to see if minors are allowed, I'm fairly sure it would be OK.
Know nothing about Paris. Have fun!