ajohn

The photos are not too clear but the three birds highlighted by John H (which are visible in all three photos) look to me more like Asian Dowitchers - straight, all-dark bills, white (not barred underwing) and clear projection of the feet beyond the tail. It's late in the year for these to be around - perhaps non-breeding birds that will stay in Hong Kong for the summer.
The other birds are Black-tailed Godwits.