Hello, sorry for such late response. I cant answer your first two questions but i worked on your third question before. There is a book about sniffing CanBus data. This document focus on how to filter and analize CanBus data obtained from your vehicle. Depending on model year of your car you may not access to your data via OBD socket, if you can access to your canbus you can write a program to analize your data or you can use other tools.
In order to analize your data you must know certain things about OBD. There is a message priority in canbus, this means more important messages has smaller ID. For example you may find your door status at 0x482 while your crash sensors at 0x02. You can use this information and change count of the messages to sniff basic information from your car.