No, apologies if this wasn't quite clear- it's the way other posters have interpreted it: Checking in at the MH counter in Melbourne as that ticket is MEL-KUL-MEL only but booked through Qantas using QF frequent flyer miles- no QF segments on the entire trip at all. Then the trip KUL-CDG-KUL is booked directly with QR as a revenue fare on QR metal only.

And MH's official guideline from their website FAQ is now double printed and saved on my phone in case I run into any problems

Thanks everyone, very helpful and greatly appreciated!