I shoot at Marina Bay regularly. Please visit my website for my professional work. If you wish to see samples please email me.
I suggest you do an early morning shoot at Merlion area, Gardens by the Bay or you can do a night shoot around Marina Bay Sands and Fullerton area. Day shoot would look a bit more lifetstyle or editorial, night shoot would be more suitable for a luxurious look.
Or you can do both day and night. Regardless, I would shoot you all on a weekday, I cannot recommend doing a shoot on weekend. On a weekend, your photos would be full of people surrounding you.
Lastly you can also book a hotel at the area if you have budget - I have actually done a hotel shoot for a family client before at Sofitel Sentosa.