Hello,
The NY Aquarium did have 1 (or more?) Orca, a very long time ago in the late 60's, when they were first being captured for Aquariums. You can see some photos of her here:
Lupa
Unfortunatly, she died after just 8 months in captivity.
Bottlenose dolphins were kept there for a while too, in what I'm assuming is now the seal/sea-lion enclosure? The pool size actually doesn't look too bad, so not totally sure why they left.
Belugas were exhibited there for a while too, however they were re-located to the Georgia Aquarium, on a breeding loan. I'm guessing they still belong to the New York Aquarium (?), and since they are on breeding loan it can only be assumed within the next few years if a few beluga calves are born, some of the Belugas may well be moved back to New York.
The Belugas from NY at the Georgia Aquarium are Natasha and Maris Sadly Marina The Beluga was also from NY, however passed away at The Georgia Aquarium.
The NY Aquarium is planning a revamp soon also, however there arn't any talks of dolphins or whales returning, although like I said this may change in the future.
Hope that helps
Ollie