Andaman and Nicobar Islands? No (Wikipedia tells me they are in the Bay of Bengal).

Interestingly, Wikipedia shows the Indian Ocean going as far as the Malay peninsula and therefore including my guess. However that does also mean that several hundred Indonesian islands are also possibles.

Sentosa? No.
My reading of wikipedia is, roughly speaking, that there is one pretty broad definition of ocean, whereby pretty much all salt water is included in one ocean or another. Within these oceans there are then various pieces of water that have their own names -- example, the Bay of Bengal is part of the Indian Ocean. But there is also a narrower definition, in which the oceans are basically all the unnamed left over bits.

Excuse me for having 2 goes in a row - but at least it's not a guess at the answer.
That was my understanding as well, but I hadn't really thought about the implications in that part of the world, if you're going to say that you go directly from the Indian to the Pacific ocean.

East Indian? No.