Regarding adr time:
They will seat you if they can.
Under 10 minutes late, they will almost definitely seat you, but you will have to wait a bit so they can work you back in. You will not be seated immediately.
If you are 15 minutes late, they will most likely seat you, with a wait, but not guaranteed.
If you are an hour late, they still could seat you. This happened to us. FIL left his insulin in the room. By the time we went back for it, we were over an hour late for coral reef. They sat us, but we had to wait about 45 min for a table.
Best advice is try to be 10-15 minutes early so you get seated close to on time.