Actually I am curious why would you have the interview as in the consulate page I have the following statement.
The U.S. Consulate General Hong Kong and Macau is currently offering IR1, IR2, CR1, CR2, K and EB5 immigrant visa appointments and all classes of nonimmigrant visa services.
I am so depressed as I am LPR and my spouse petition visa isn't in the scope. Your case is a candle in the dark.