I voted to come out and so gain control. If our decision is that it is best to change everything immediately, then so be it. If our decision is that we need to make changes gradually, then so be it. Our elected governments will do their job.
The only thing we need to watch is any attempt to get out on paper only and still tie us into all the unacceptable impositions we're trying to leave behind.
That stated I'm sure that the government knows there is no chance of accepting free movement from day one. Folk will need passports/visa/whatever is decided upon. No idea what is meant by a tribunal structure, our courts will decide what goes here even if the existing law remains in place (minor working edits excepted) until they are reconsidered. Customs union will depend on the details, where the devil is allegedly. Again retaining any impositions that we voted to get away from, is unacceptable.
We still have to see what a possible agreement will be. Anything else is presently just personal speculation from folk with personal reasons to push a particular view.