What is it that you are trying to achieve? You initially asked about stopover in MN on a trip to SIN, than considered BKK, now, you are willing to thro away the last leg, MNL-NYC.? Do you really want a one-way to Manila?
It's difficult to provide advice without knowing your real objective...
PAL doesn't have a formal stopover program, so fares including one are luck of the draw. If you know somebody at PAL or have a good agent in Manila, they might be able to help you find the best option.
For a one-way NYC-MNL, miles are the best way to go. Nonstop on PAL or one-stop on any of the alliances.
If you are considering alternative airports in Asia, LCC are the best option for one-way fares - i fly in and out of MNL frequently and PALs oneway fares originating outside MNL are rarely competitive, even after considering luggage, food & service.