Hi Astrid,
I hope you and your family are having a great time in Dublin! You may have already visited Dublin Zoo and experienced Wild Lights by now, but I still hope this information is helpful.
It seems like your research was spot on. For Wild Lights, you'll need a separate ticket. Wild Lights opens at 5 pm, which is when regular zoo opening times end. Most animals will be in their indoor enclosures by then, enjoying some rest and warmth. If you'd like to see them, you'll have to get a separate daytime entry ticket to the zoo.
If you're worried about the costs, this could be a nice alternative: You might have already seen some buildings in Dublin beautifully lit up. This is part of
Dublin Winter Lights, which can largely be enjoyed for free.
I'm very curious to learn about your experience in Dublin with your kids!
All best,
Noortje