We are still waiting on one of our party’s passport (the youngest of our family - 2yr old) can we check in using his birth certificate and change his identification to his passport when we arrive at the terminal? Do we have to do online check in or can we just check in upon arrival? How long can we wait to do online? Don’t know if it matters but we are traveling Haven so do we have specific time or do we board whenever we arrive? Appreciate anyone who can answer! Thank you!