Sorry for not making it clear...

We are taking the SIN-BKK-SIN legs with AY in J, to add some extra QPTS...

The DONE route is this:

CMB-HKG-LHR-AUH-LHR-IST-LHR-YUL-DFW-ANC-DFW-SFO//LAX-SJU-JFK-HKG-SIN-CMB.

None DONE tickets are:
ICN-HKG-CMB with CX (J) to start
LGW-FCO-LGW BA to visit Rome
LGA-DCA-LGA AA (Eco) to have a look around DC
SFO-LAX AA (Eco) to connect to SJU flight
SIN-BKK-SIN with AY (J) QPTS addition, and a little shopping
CMB-HKG-MEL CX (J) to get home

After returning to MEL there will be the following in QF economy:
MEL-PER-MEL
MEL-BNE-MEL
MEL-SYD-MEL
MEL-LST-MEL

We need to add another 2-3000QPTS I think, to get to ExPlat with AA.
If we use MCT instead of AUH, that works to add a few hundred more, but I am stumped on how to add the other 2000 or so cheaply.
A BA or IB I class in Europe perhaps?

Any ideas? The DONE routing might have to reversed, with SIN, then on to HKG and JFK, but the cities will stay the same (barring the AUH/MCT substitution...)