The answer to your first question is that you will have enough time. BOM international and domestic are essentially two different airports in the same city. You will need to do immigration, claim bags and customs and then recheck your bags to Kingfisher. You can take the international to Domestic transfer bus ~20 minute ride. I suggest that you contact Kingfisher to confirm that there will be a Kingfisher transfer desk after international customs clearance. (I flew NW to Jet, but I think it is just next to the Jet tx desk). Just be aware that some of the porters in the airport will try to handle your luggage without asking you... then "insist" upon payment for doing that...