I do not suggest that you get the H1 visa in China because your current status is not h1 and it may hurt your pending I-485. You actually does not need to work with h1 and EAD is fine to use for your job. If your I-485 is denied, you just go to China to get the H1 visa and then, you will be in H1 status after you return. You can use AP to travel to China.