I am not an expert, but since you will be in Australia for at least 2 days and visiting 2 ports in NZ then you need eTA’s for both of those countries. The only time you don’t is if you are simply transiting through an airport and not leaving the airport. That question is asked during the application process.
I do not believe Canadians require a Visa for French Polynesia, and not for Hawaii/USA.
eTA’s are not Visa’s per se, merely authority for tourists to enter the country. Visa’s are for people moving there. The eTA will be electronically attached to your passport when you successfully apply. Both Australia and NZ have an eTA App to download and use for your application. As mentioned previously, NZ also charges a tourist levy on top of the eTA, much like a toll on a bridge or highway that helps pay for infrastructure. When it works properly, the application should go through and be confirmed quite quickly, as soon as your payment goes through the confirmation should arrive by email if all is in order.
if in doubt, speak to your travel agent.