Check the ANZ website which will tell you if you change aircraft at HKG - I suspect not - in which case they'll want you off the aircraft whilst it's cleaned. Also gives you a chance to stretch the legs whilst "in transit". Havent done CLK but it cannot be worse than the old transit box at LAX and that was before 9/11. I, too, have avoided the US since 9/11; before they were just b******y rude now they are paranoid.
ANZ are amongst the best although I hear legroom is not as generous as it once was. The days of three seats to your self are long gone. Pre-book; and turn up early at the airport to make sure of a reasonable seat. With so many people having access to the booking systems the ordinary SLF seems destined to suffer with the worst seats.
Sit back and relax - you'll need to after suffering this insane "security" nonsense that is inflicted upon us - but has yet to stop anything. Plenty of water - no alcohol - little food - and start working on NZ time as soon as you leave - then you will suffer little from jetlag. There are those of course that claim to suffer jetlag back from Greece to UK on their summer hols.
Auckland Airport getting better all the time - it can now cope with three 747's at once.