look for a small restaurant.... book the whole damn
restaurant... then ask the restaurant to prepare a buffet spread
for how many people (you decide).. then invite relatives and
friends along...
That way, you will be having your party in an air conditioned
place, you will have a buffet spread, your parents, relatives and
friends would all have a place to sit, everyone is comfortable and
not sweating (like bbq or chalet), no mosquitoes, no distractions
(like chalet, people from adjacent units can be quite loud
etc)..
The most important point is, the waiters and waitress of the
restaurant can still serve you and your guests. You will still be a
customer to them.
Booking a chalet is already quite expensive, plus your buffet
ordering and bbq stuff it can add up to quite alot. The booking of
a small restaurant is also around that price but maybe slightly
more expensive.
If you want, you can try Fig "n" olive restaurant (not the one
at vivocity but the one at the bencoolen area), I tried doing
something like this before, it was fun. The place can host up to 50
people... Have fun exploring..