Hi
Is museum of ice cream
River wonder and night safari
Possible Comfrtably without being hectic?
River WOnders and Night Safari make a sensible day together.
I avoid doing much if anything before lunchtime on that day - though something small that isnt an early start like the Museum of IceCream might work. Remember whatever you do during the daytime you are going to be going on until well past 11pm at the Night Safari if you go in at opening time. Lter entry pushes the finish time back as well
However - on Day 1 in Singapore after you arrive presumably from India the idea of the Night Safari is supremely bad. Even if Day 0 is your arrival Day I'd push it a bit further to ensure being sensibly time adjusted and rested which is vital for the Night Safari.