There isn't much to optimize or choose from given that you are on an xONE3. You can only do Asia-NA-Europe and 17 segments, so have to buy 3 additional segments to max it out. I personally think HKG-YVR-JFK is inferior to HKG-SFO or HKG-LAX but everyone has different considerations and the differences aren't really that great. As you are collecting in AA the thresholds in segment length don't matter to you, which eliminates most of the routing fun. What you can do depends on the season when you will be flying, for example sometimes LAX-SXM operates as a single flight number (but not the last time I looked). LAX-SJU nonstop on a 763 is a good flight, but only operates 1 or 2 days a week. Remember that NA includes everything in the Caribbean and north of Panama -- which can make for some interesting destinations but not particularly good flights. As for going to Europe, the rule is to leave from west coast (makes for a much more pleasant flight). If you need to credit that to AA, as you suggested, then JFK-YVR-LHR would be the best use (alternative is MEX-LHR or even one of the Caribbean routes on BA).
I suppose you could pay the differential and convert your AONE3 to AONE4 and add SA, that might be cost effective. I personally think the xONE3 are poor value compared to 4 or 5 continent (even with the 20 segment limit) if you are trying to maximize FF earnings.