Possible location:
esplanade waterfront - MBS as background
esplanade bridge - blocked with canvas
Merlion water front - Firework directly above MBS (wide angle lens is a must)
along One Fullenton waterfront - wide angle lens is recommended
Cliffer pier - Firework will be above floating platfrom. May capture MBS, Flyer and floating platfrom as background or esplanade to Flyer.
Marina waterfront - esplanade to Flyer as background. Wide angle lens not needed. Space is limited.
Marina barrage - not recommend as fireworks are in line with MBS.
MBS waterfront - CBD as background, wide angle lens maybe required unless Fullframe.
Helix brigde - one fullenton to NTUC building as background. Will be able to capture main fireworks and small fireworks from NTUC building and others, wide angle lens is required to capture fireworks from buildings.
When the about location required wide angle lens, it means lens that are under 17mm. If yours are 17mm above than find a location that doesn't need wide angle lens. Statement Not applicable for Full frame.
Good luck.