About 3), here
https://www.google.com/search?client...nt+from+abroad are some old threads about opening NZ bank accounts while still overseas. I suggest you look on the various banks' websites to see what their current policy is, and you could contact them to ask your question about not being able to activate the account in person for quite some time. (I can't see why any bank is likely to object to holding money, now I come to think about it!)
See here
https://wise.com/gb/blog/new-zealand...nheritance-tax also. It seems you will not be liable for any tax on your inheritance under NZ law. And looking here
https://moneytothemasses.com/tax/rea...ed-from-abroad, it seems you would not be liable for UK tax on the money, either, only for any interest you earn on it if you invest in some way - which, although the first website doesn't spell it out, I imagine would be the same in NZ also.