I went to Google and did a search on "climate auckland new zealand"
Auckland.jpg (25.3 KiB) Viewed 8145 times
and another search on "climate wilmington north carolina" (in the heart of Venus flytrap country)
Wilmington.jpg (24.44 KiB) Viewed 8145 times
Temperature-wise, they're very similar during winter (I'm talking about the season, not the months on the calendar). This is great for the dormancy requirements of Venus flytraps and Sarracenia. However, the summer temperatures in Auckland are much cooler than those in Wilmington. You want to give your flytrap and Sarracenia at least 8 hours of sun, preferably from dawn until mid-afternoon. In addition to the sunlight, you're also trying to warm up your plants. If you can put them close to a south-facing wall, they will get extra warmth from the heat radiating off the wall. For water, it has to be low-mineral: 50 PPM or less. Flytraps like to be damp, and Sarracenia like to be a bit more on the wet side.
You didn't say what species/hybrid of Nepenthes that you have. Nepenthes are tropical plants, but their temperature requirements vary depending on whether they're lowland, intermediate, or highland species/hybrids. The most commonly sold Nepenthes lean toward lowland conditions. They like to be warm and humid. For sunshine, start off with sun from dawn until noon and then dappled sun or bright, indirect light for the rest of the day. You can use the same water as that for the flytrap and Sarracenia. Nepenthes like to be damp but not flooded. If you keep it constantly wet, then rot is likely to set in.
I can't give any advice on the sundew without know what species it is.