As of the last sailing at Brooklyn, there are no food and drink machines located in the Brooklyn Cruise Terminal. The line did offer canned water after the final check in of document, photo and scan of Passports. It was located btw the General Assembly Hall for Non Grill Passengers and the Grill Lounge,
We did not have to use the rest rooms so can not confirm about baby changing tables.
The elevators in the Brooklyn Terminal are located pass the Escalators to the rear of the First Floor. It will take to you to the level equal to the top of the escalators. There you will be directed to the Gangway which is in two (incline) parts to the Bulkhead entrance of the ship.