No, to my knowledge, license transfer can't be done from Australia.
Turnaround time in PNG after having successfully sat the air law exam to having a PNG license = a few weeks if you have a good run.
Yes, easier to convert the NZ CPL to PNG as opposed to Aussie as the PNG rules are now based on the NZ framework.
Can't help re Brisbane DAME's but I know there is at least one DAME in Cairns who does both.