✔ 最佳答案
1. It depends on the stage of your application.
If you are waiting for a visa quota (the long wait), you can still apply for a visa, providing you will answer all the questions honestly (especially about the question that if you have applied for immigration).
If your application is currently in process by the NVC and the U.S. Consulate (you should have paid AOS fee and submitted DS-230), in that case, you should avoid application unless it is emergency.
2. It depends on the appointment interview schedule.