Yes. It is possible to register or change the licence number of the vehicle up to 24 hours before departure for an extra fee of 30 NOK (approximately 3 EUR).

The current answer is that all vehicles, except for motorcycles, are required to pay tolls in Norway.
Read more here: AutoPASS: Easier travel on toll roads in Norway.

Yes, you can do this through My Page.

We recommend measuring your vehicle yourself. Start measuring from the front of the vehicle and go all the way to the rear of the trailer or caravan. If, for example, you have bicycles attached to the back, these must be included in your measurement. We require the total length. The same applies to the height. If you have a roof box, trailer, or any similar attachment on your vehicle, it must be included in the measurement. We are looking for the highest point on the vehicle/trailer.

Providing incorrect length or height may result in additional costs for you as a traveller and, in the worst case, you may not be able to join the journey.

There are separate areas on deck for parking motorcycles. The driver must secure their motorcycle with two straps that can be found in the designated parking area for motorcycles. You can see how here: How to park your motorcycle