100% #2.
First of all, you won't be subject to import duties, which are impossible to estimate. Could be 10% easily which would make up the difference, pretty much. COULD be more. Could be less also. And it can take years to have duties assessed so you can't know immediately. But you also with a Singapore seller risk a bag stuck in customs and IF it were identified as fake it might be seized. Too much uncertainty there for me personally.
Secondly, the Singapore reseller (is it Singapore or Malaysia?) is asking for $2K without the images you need for authentication. This is sketchy. If they are trying to withhold details that could help a scammer or counterfeiter, I can see that - then they should have a certificate from bababebi already - I personally don't sell high value bags without them.
Thirdly (and I am assuming here) sounds like you will have a written agreement for exchange with the US reseller. This plus them being US-based would help you in any PayPal or credit card claim you might have to make in worst case. And will help you if you don't love the rose gold (personally it bugs me that RGHW does not match the heat stamp and zipper, otherwise I would love it).
The biggest Q is - how are they asking for payment? I will never, ever, pay for an expensive item, that I have not examined in person, by wire transfer. If either seller asks for this, run away quickly. With PayPal you have pretty strong buyer protection (I don't know if it has an upper limit). With most good credit cards you will also have purchase protection but it may not be over $10K.
Good luck!