It's bonkers isn't it, what is going to stop rogue drivers from simply carrying on up the A63 without their checks on arrival, once they leave the dock? The lorries that most need to be inspected by customs will probably be the least likely to actually comply. Our dock infrastructure, what there is of it, was not built to anticipate this.
The impact on traffic for all the sites mentioned will be huge. The roundabout off the A63 at North Ferriby/Hessle West regularly clogs up (in pre-COVID times anyway) at rush hour - it used to take me 10-15 minutes to get off the A63 and get to the roundabout if I timed it wrong, because it was backed up from the Bridge. Both the Walton Street and Humber Bridge lorry park options are going to put more pressure there, and I'm not convinced the junctions have the capacity to cope with the existing traffic, let alone more.
Plus we all know what the A63 is like anyway, with one broken down lorry on Castle Street bringing Hull to a halt - only now with added roadworks for the next 5 years.