Doing business in HK - Do's and Don'ts

[intercultural]

Hi Everyone!

I used to live in Singapore for almost 5 years but coming Thursday I will advise some people who will work in Hong Kong. They are based in Germany but will travel to Hong Kong in order to implement an IT system for the local branch in Hong Kong.

For following questions I would like to get your views, ideas, thoughts:

We would like to leave a first positive impression on our colleagues in Hong Kong - what should we do/what should we avoid?
Our project will be around business process optimization and we will have to interview several local colleagues - anything we should observe?
Running end user trainings, running workshops - how is this done in Hong Kong?
Communication: When is a yes a yes? How to get feedback, proposals for improvement, etc from the local colleagues?
What would you say are the biggest differences between Hong Kong and Singapore and mainland China?

Thank you very much for your help! Any advice is highly appreciated!
Cheers!