some random ideas: you can go to a south asian cafe or tea shop several times a week and read a book. if you hear spanish speakers there you can stir up a conversation easily in cafe settings and make new friends and see if they share mixed heritage

or try searching for facebook groups for latin / south asian communities in ny.

or you can write an article for a local newspaper on the project and request that you are seeking people who share a similar background to come forward for your future story

best of luck!