I can answer at least the last point from a liability standpoint.
The language of the legislation requires companies to ensure that a defect is corrected before the vehicle is offered for sale, so it's not an obligation that is absolute. The obligation imposed is to take reasonable means to ensure that the goal is achieved. They have to demonstrate that they have done everything within their power to achieve the goal. They obviously cannot be held responsible for something that dealers would not be willing to do of their own volition to respect a contract that might exist between themselves and the dealers. They would not be held liable for something that is completely outside their control.