Forget New Zealand. The flight's far too long for young kids.
Although Dublin's a lovely city, it's not massively child-friendly.
I suggest visiting Paris but not actually staying at Disneyland. (You can still visit it for a day, or perhaps two, though if you want to. It's easy to get to). Paris itself has plenty to do for kids, with the wonderful Jardin d'Acclimatation being it's star attraction. (
https://www.jardindacclimatation.fr/en ). Your kids would enjoy it just as much as Disneyland Paris, at a tiny fraction of the cost.
Alternatively, of course, the beach resorts all have their attractions.