I think the drinking age in HKG is 80 dollars. I never saw id requested, and HKG is very materialistic. Lots of great bars but I can only help you with the expensive ones. A "must see" is Felix at the top of the Peninsula hotel, great bar and decor. Be sure to sit at the glass table facing the right way. The restaurant part is expensive but the bar is actually a bargain for what you get.
As for suits, there was quite a discussion about this in the
Mileage Run forum (now you know why some people make mileage runs).