Hi all, thanks for all the advices.
My SFO flight with SQ has already been booked and can't be changed.
Took your advices to opt for a later connecting flight and have booked AA.

Would like to seek your advices re checked bag fees..
I came across these 2 links:
http://www.aa.com/i18n/utility/baggageExceptions.jsp
http://www.americanairlines.com.au/i...eAllowance.jsp

The first link mentioned that the 1st check-in baggage will be free for customers traveling to or from destinations in Brazil and Asia (I'm coming from SIN, transit in HKG).

The 2nd link only mentioned that checked bag fee will apply if the domestic ticket is issued separately to the international ticket and travel on the domestic flight is outside of 24 hours from the international sectors.

Given my scenario:
SIN-SFO via SQ arriving SFO at 1945
Transfer SFO-JFK via American Airlines, departing 2300
Separate PNR

Will I need to pay for my 1st checked in baggage?