Not likely. I was in Singapore a couple of years ago the first week of March. It was 95 degrees Fahrenheit(Tropical Climate) when our flight landed in Singapore. Hours earlier our flight from Beijing took off where the local temp was -7 degrees Celsius (That's below freezing).
Hong Kong probably gets temps in between what Singapore and Beijing gets. However Hong Kong gets their share of freezing temps in the winter. Been there in Winter several times. Peacock Bass is not likely to endure their Winters.
You might see them in some HK local tanks or heated ponds but not in other local waterways. You might see them also in some Restaurants, sharing tanks with Live Tilapia or Perch ready to be cooked to your specs.
Snakeheads should be easier to find, in the market or local fresh waterways.