You could transfer Chase plus some AMEX to VS and book ANA for 95k/person in business class for TYO - NYC - TYO (or splurge and transfer it all to ANA and do F for 120k/person).

Then use AMEX to BA (check space first) to book JL J on BKK - HND/NRT (and if you need to spend a night at HND/NRT and enjoy Tokyo). Haven’t done the math (aka you might have to do JL Y).

Also worth checking what the cost of just SIN - NYC would be (again don’t have it handy). The BKK - SIN flight is short so if you can get SIN - NYC for 140k you could just buy BKK - SIN in Y (we did something similar for our honeymoon where we did NYC - SIN in F and then purchased SIN - DPS in Y since it wasn’t worth extra miles)