AP or NOT?

I just got I140 and I485 receipts. I am planning to home around the end of year or next summer, and am thinking whether apply the AP now.

I have three questions:

1. Would the AP application affect the I140/I485? I mean the CIS might be more stricter with the I140/I485. They said they did not like people file 485 just for AP.If it is that case, I would not apply AP until the I140 (at least) is approved.
2. How long will it take for AP (in California Center)? If it goes fast, I can wait a while.
3. How long is the term of AP's volidity? If the volidity is short, I perfer to apply a bit later.

Any comment would be greatly appreciated.