首先申明我不是律师,个人意见仅为大家提供写帮助,仅为参考:
1.Priority date:
I140 approved, you will get I-797 approval notice, you can find it. If your I140 are still pending, the PD ususally is one workday earlier than your recvied date in I140. Currently All applicants for I485 (E based) (except its priority date is before May 2000) have to wait the visa number to current. Especially the recent filed one have to wait to 5 years to be currrent (theortically) or even longer (refer the visa bulletin)
2.Which center handling docuement faster?
Currently, for I140, all depends, I got approved from NSC in 5 days. But from many cases, It seems TSC is faster than other centers.
3. Any exception for I485 approval?
Yes, Even you just sent your I485 (E base) before Oct.1. There is still a very speical way to get it approval. I would not disclose the way I did it. But I would to say, relation IS still working in USA!!!
4. AP
After you using AP, you still can keep you H1 in your current empolyer,but after you change the job, it is unclear area. some cases still support that you can keep H1, others don't.