they will have to be in country as your wife will have to have the blood and xray tests followed by fingerprinting. Assuming your stepdaughter is under 18, all you will need for her is blood type certificate and as previously said, adoption paperwork. Of course you will need marragige certificate and passports. They can arrive on a visitor visa (from the airport on arrival) which you can extend for 1 month. If you havent got it done by then, they have to leave the country briefly (return trip to Bahrain is the cheapest). You cannot apply for their RP's until yours is complete, then it should be fairly plain sailing achieveable within a month.
Hope this helps