We had someone in our group who did the Sky Tower bungy on their own before, the AbD started. Depending on when you are arriving in Auckland, this could easily be done on arrival day afternoon or on the first AbD day as tour activities do not start until a group dinner on first night. Since it’s only open until 5pm, there would not be time to do this after your Waiheke Island day as the ferry get back around 05:30pm
Also to note its not really a bungy as you don't bounce around, you go straight down in a controlled descent of up to 85km per hour (so not a freefall). I have not done it but from memory of watching people do they can also stop you in front of the viewing floor on the way down.
We had planned on going to the shotover canyon drop outside of Queenstown the morning of our post day, as our flight didn't leave until 3 pm, but had trouble with the reservation. They were going to work us in, but it would be a close call. and then we had airline issues where our flight was cancelled the night before, and moved forward in time making this impossible. You might consider this as well, as it is pickup/return from the hotel and appears a lot more wild. It didn't happen for us, so I can't tell you more. The people are very accommodating and helpful, though. https://www.canyonswing.co.nz
Nope. Never gonna happen. Nope, nope!!!
