Yes, BOS-NWA, you can use your parents' address in China. As long as you are gold or Platinum on NWA with an Asian address, you do get free WC lounge access--even in affiliated lounges. For example, I was flying "Go" (BA's old low-fare offshoot) a few years ago from London Stansted airport, and spent 2 hours in the KLM lounge there. Every International Airport in Northwest or its partners fly to will let you in. I still spend about 6 months every year in Japan/China/Singapore, so I don't really HAVE a home address that is consistent. This has always worked for me.

I think NWA allows lounge access because most of the Asian Gold Elites don't get a chance to take advantage of the main reason Golds like NWA in America: Free Domestic EUAs. So they sweeten the pot this way.

I think you'll get a new card mailed to you in China. You can keep a U.S. billing address on your World Perks account here, and always e-ticket, and so YES you can use the U.S. Elite phone line. In fact, when I'm in Asia, I still often call the U.S. line because the agents are so excellent.

So you don't really need anything to be sent to your China address except your membership card.