I-485 pending for 4 months (change of employer)

[xyzextra]

I applied for I-140 and I-485 concurrently on Oct 1, 2011.
in Nov, 2011, I already got my EAD card and Advance parole papers.
in Nov, 2011, I also got my fingerprint taken.
In early Jan 2012, my I-140 got approved.

I have following questions:
1. When can I work for another employer?
2. In concurrent filing, can NSC start security checks and other procedure related to I-485 without I-140 being approved. So, as soon as I-140 is approved, I-485 can be quickly approved?
3. I am born in India, having a European (Netherlands) passport. Does my I-485 processing go to India queue or European (Netherlands) queue? in any case, what is the waiting time expected?

thanks in advance,

[xyzextra]

forgot to add that I-485 filed as EB1 Multi-national manager category.