Would TG be the best choice for MUC-AKL in terms of quickest, most convenient, least number of changing planes, and service? I also assume for both MUC-BKK & BKK-AKL, TG uses the A346 which means they have the latest F product installed is that correct?

Between November and February, TG will be switching their BKK-AKL flights to a 772ER, which will have the new C product, but no F cabin onboard, apparently. See this thread in the TG forum for details:

http://flyertalk.com/forum/showthread.php?t=725866

If you're willing to fly C instead of F, another good option for the route is to fly MUC-HKG-AKL with LH (on an A343) and NZ (B744). Both aircraft will have their airlines' respective new C, the Lufthansa aircraft will also have a First cabin. And new C on Air New Zealand is supposed to be excellent, better than F on some airlines.

If you really want to fly F into Auckland, Singapore Airlines appears to be your only option at the moment, which means you'll have a two-stop itinerary (MUC-XXX-SIN-AKL), where XXX could be FRA, ZRH, MXP, CDG, wherever...

Non *A there is also EK (A345 via MEL).

Non *A adds several more, act. You can take CX to HKG and AKL (or NZ from HKG)...much better than LH. JL? LA?

CX doesn't have F to NZ. JL doesn't fly to NZ at all (it codeshares on NZ). LA requires 2 or 3 stops MUC-FRA-(MAD-)SCL-AKL or MUC-MAD-SCL-AKL.