Company is about to offer me a relocation to Hong Kong

Hi everyone,

I am from small country in Europe (Serbia), and I work in an international company from USA for year and a half now. Currently, I am engaged in few projects in APAC region, and one of them is our big client from Hong Kong. Due to timezone difference and huge scope of the project, my presence there became required. I am a business analyst in a software company that delivers end to end cloud solutions.
Now, I am married and have 2 years old son. Company started the initiative on relocation based on my manager (from APAC) recommendation. Soon, I am going to have a call with the HR to discuss terms and everything.
Can you tell me, please, what is it that I should ask for? My wife would have to leave her job here, and start seeking in HK when we are there. I was in HK twice this year, and I can tell it is really expensive. Our plan is to settle first month without our little son, until my wife finds a job and the babysitting service, since that is really important to us.
Is there anyone that you know with similiar situation who I can ping to get the more info.
One thing to consider is that our subcontractor in HK is willing to participate in a budget for relocation.

Thanks for your time and your advice.

Milis