Guru's:
1) After replying to a I-485 query, does INS will ask us to go to interview in the local office
Rarely. Unless they are not fully satisfied with your reply to RFE.
2) How does the INS inform about the result of the query, if it is appproved will they send GC papers to us
Yes, if you submitted whatever they asked for RFE, they probably will approve your case and send approval letters (not GC papers) to you and your attorney. You will use the approval letter to get your passport stamped at local INS (this is not an interview people is talking about, since you have already been approved).
Unable to understand the procees please help
Stay in the forum for 1 month and you will understand everything. Plus go to BCIS's web site and lawyer's web-sites. You will get lots of information.