NZ company - NZ employees of an NZ company - taxed in NZ - paid in NZD in NZ. Australian law not relevant as they aren't resident in Australian for tax purposes. Just because you undertake part of your job in aussie that doesn't mean you owe australian tax (think of a salesman who works for a NZ Company lives in NZ but spends time selling goods in Aussie)
Mostly correct.
Think the employment contracts stipulate Australian Law for disputes.
Also, in some jurisdictions tax law stipulates that if a certain percentage of your job takes place in the jurisdiction then you can be taxed in that jurisdiction regardless of where your employer and you are tax resident. America is particularly nasty on that front, they will reach out and grab tax from citizens working overseas. If you're on an expat deal with your company, get tax advice!
Not the case in Australia I don't think, but I'm no tax lawyer (thank god).
Incredible stamina. No shame. Yellow Fever.