He seems to have a solid plan, but I think it can be improved. Most of the time there is only one person in a car, but like this guy has, there should be a contingency for family, or multiple passengers. . He stuffed enough gear in one bag for four people. Well, if there is going to be at least one other person if you need additional supplies, then why not do two bags.
The first bag is the drivers bag. It will have all of the necessities for one person, and with all the bags space for one person, he can put in more, or perhaps better options in the bag. For instance, if he wasn't carrying 5 of everything, he could get a better bivvy and vacuum pack it. He could have better meal options,. Instead of a tiny pepper spray, a larger can of bear spray (or both), extra socks, better FAK. You get the idea.
Second bag would have the extras. Extra food, water shelter, ponchos, protection,, etc. All the stuff from his setup that he was humping for other people.
Why should everything for everyone be stuffed in one bag, no reason for it, It's guaranteed that if bag 2 is needed, there will be at least one other person there to carry bag number two.
I did like his idea about the water key. It does not take up much space and it expands options for the most critical of supplies, water. Then I got to thinking, if he has the multi-tool with pliers, does he really need the water key. Still good outside the box thinking.