I am planning my itin and have the following:

SYD-BNE
BNE-MEL
MEL-LAX
LGB-BZE
BZE-DFW
DFW-LAX
LAX-JFK
JFK-ORD
ORD-LAX
LAX-LHR
LHR-IST
IST-LHR
LHR-DXB
DXB-LHR
LHR-SIN
SIN-HKG
HKG-NRT
NRT-MEL
MEL-SYD

1. I understand the continent of origin 4 segs 2 stopovers rule - but is there a limitation on doing all continent of origin segs either at start or end - or can I split them between start and end as above?

2. My start point is SYD. But the NRT-MEL seg is one flight number (QF22) but stops in SYD. Does that mean as soon as I get to SYD my trip is over OR bc it's one flight number I am not considered to be going through SYD on that seg?

3. Any other problems you can see?