Yes, iPhone 8 does have Dolby Digital & Noise Cancellation.
Yes, iPhone 8 does have the OTG support.
We are extremely sorry to inform you that we do not ship the products outside India. Further, we also suggest you buy it from Singapore only so that you can get the warranty for the product. Only Apple iPhone X comes with the international warranty.
Yes, Apple iPhone 8 does have the OIS. It helps greatly with blur in the event of shaking hands or dim lighting and the larger sensor consistently picked up more light for better low-light photos.
No longer the gold standard, the iPhone 8 is still all the phone you need.