1) Correct: Any matrix damage attack (data spike, resonance spike) against the vehicle is instead applied to the device the Rigger's persona is formed on
2) No, only if the matrix damage has been modified through a program to do so. Real damage to his vehicle on the other hand is applied as half that amount as bio feedback damage against the rigger (if he is in cold or hot sim)
3) Slaved gear defends with the better values of firewall and pilot/willpower. Once the RCC is out of commission, they count as unattended and use their own firewall and rating to defend
p.237 core:
"When a defense test calls for a Mental attribute, use the owner’s rating. Even if she isn’t currently defending or even interacting with the device, her previous interactions and settings affect the defense test. If a device is completely unattended, the Device Rating stands in for any Mental attributes an icon needs but doesn’t have. For example, a device that an owner sets and forgets, like a door lock, uses its Device Rating in place of Intuition as part of the defense pool against a Control Device action."
4) He still can jump into them, but it takes double as long from AR
"Jumping into a vehicle is a Complex Action if you’re in AR, or a Simple Action if you’re already in VR when you make the jump. If you’re using a direct connection and already plugged into the vehicle or RCC, you can jump into a vehicle directly from your meat body by taking a Simple Action." p. 266 core