Greg's Seafood Shack

Not much. Only the pool area. But the hotel has a lot of family guests

They have centralised aircond that are control through the hotel's app available on the phone beside the bed or you may download the app for full control of the room's lighting, temperature, toilet blinds and so on.

Tap water is safe to drink in Singapore. Moreover, some complimentary mineral water is provided by the hotel everyday.

Yes they do

Probably those are not part of the features required for 5*.

ya they hv subject to availability