1. Other than for legal authorities, who do you stop for?
I would likely avoid so called legal authorities as much as possible if I have an actual goal in mind. As for stopping to help someone along the way, if it is someone I can help with minimal effect on my self rescue, I probably would. If it is someone I cannot help at all with the resources I have available, I will note the location and report it to someone who can help when I can do so. There are various degrees of ability to help between those two extremes that would require a decision based on the actual circumstances at the time.

2. What is your response to those who want what you have?
"Pound sand". Unless they are better armed and have the drop on me. Even in an emergency, being dead is worse than losing some gear to looters.

3. What protocol do you follow with those who want to join you?
A decision that cannot be made without knowing the circumstances.

4. Where do you draw the line between looting and foraging for a resource you decide you need?
Another decision that can only be made based on the actual circumstances at the time.