Thank you very much guys...
Yes, it might be quite unusual getting the interview date so quickly! Here is the catch... My LC date is Jan 1998 ( yes this is correct!!). Applied under non-RIR category. RIR then just started so my lawyer didn't want to take chance. Got stuck in the biggest backlog of LC history. You guys are probably aware of. LC was approved in Sept 2001! I'm from Bangladesh and therefore, the priority date is pretty current ( not sure if this matters).
I was not expecting the interview so early and neither did I ran by any senator or congressman. Fortunately, got the interview letter in Sept.
We were asked to show financial documents ( 3 year Tax, W-2 and 3 pay-stubs etc.), current job letter, I-94 and proof of marriage ( marriage certificate and baby's birth certificate etc).
I believe it depends on the officer who interviews you. Some will give you hard time and some will be very nice to you. In general, NYC center is pretty friendly and much lenient.
Good luck to all of you and have a wonderful happy new year...