Which of these are possible to do:-

LHR-SIN-MEL-CHC-AKL-SYD-JFK (MEL=transit only, but means going back to AUS from NZ on this routing isn't allowed)

LHR-HKG-AKL-CHC-AKL-SYD-JFK (AKL first time would be transit only) - stays would be in CHC, AKL & SYD.

Looking to max out miles possible whilst not doing unnecessary flights due to medical issues.