The participant registration form must be filled out on a per person basis. If the driver does not own the car, both parties must fill out the participant form separately.
No. You only need to fill out the participant registration once per person. Once you complete the participant registration, you can fill out the car registration form for as many cars as you wish to race.
Participant and car number registration is only valid for a single racing season. Some tracks may also require separate registration for special events.