So before sending it to DOS for revalidation, make copies of everything you think it is important.
You can file I140/I485/EAD/AP together. I think it is allowed to travel with AP, but still holding valid H1b status, as long as you come back and work for the same company. But using EAD will make you lose your H1 status. If you get your revalidation and AP, just go ahead and use your H1 visa. AP will be valid for one year. So within one year, you can still go back to China and come back here again using the still valid AP.
Hope this message helps you.