Car ferry

We are heading to Japan this Christmas to do some skiing and are considering renting a car. Does anyone know if the ferry costs posted from Aomori to Hakkodate for the car costs include the passengers or is there added cost for the passenger as well as the car?
Also, would it be easier just to use a rail pass to get to and from the ski resorts?
Thank you!

Does anyone know if the ferry costs posted from Aomori to Hakkodate for the car costs include the passengers or is there added cost for the passenger as well as the car?

The cost for a car advertised by both, Seikan Ferry and Tsugaru Kaikyo Ferry, includes the cost for one passenger in 2nd class. Additional passengers pay the passenger fare separately.

Also, would it be easier just to use a rail pass to get to and from the ski resorts?

Depends on your winter driving skills and the ski resort. Many of the resorts are well connected by public transportation, but some are not. Driving in northern Japan is not recommended if you do not have previous winter driving experience. On the other hand, it can be convenient to have ones own car, especially if you have a lot of luggage or travel with a larger group of people.

If you drive, I would consider renting a car separately on Honshu and Hokkaido versus taking the car onto a ferry. The ferry trip is expensive, and most rental outlets do not let you drop off a Honshu car on Hokkaido or vice versa.

No need by car if you have JR-Pass.
Take over night Exp Hamanasu from Aomori to Sapporo next morning.
http://www.skiing-hokkaido.com/

Car ferry not cheap.