Well your DONE3 is still one sector light in Asia, so at the very least get it ticketed as:
CMB-SIN-HKG-LHR-AUH-LHR-IST-LHR-YUL-DFW-ANC-DFW-SFO//LAX-SJU-JFK-HKG-SIN-CMB

even if you plan to go straight from CMB to HKG (unless the QF Plan somehow gives more points for a single flight of 2494 miles than two totalling 3298). To minimize the risk of the miles being merged together even with two coupons you might want to get off in SIN and continue on the next flight to HK 2 hours later.