Either boat/bus to MK then bus to AKL or bus to AK then bus to AKL. My guess is the bus to AK won't be running that late so scratch that idea.
You really should allow an hour, only because you could be waiting 20 minutes for each trip.
I'd allow even more time and plan on having a drink in the bar. You'll get a beeper and your table might be ready early. I'm not sure how late they serve dinner. It doesn't matter if you're late for most ADRs but not if they've stopped seating guests for dinner.