I can’t agree with your solution for water purification. If the argument is to “also” include scenarios where boiling isn’t practical, there are other options that fit the bill. For us, we’ve been using a Berkey filter system in our home instead of something that needs water pressure or power to serve in both bug out and Flint, MI like scenarios. We use it day to day today. Not cheap upfront but the cost per litre/gallon over time is a fraction of what you’ve proposed – with all due respect.
Call ahead to the meat dept.of your store and ask them if they can hold suet or fat for you, what days they ate most likely to have it in inventory, and whether or not it has to be special ordered in the quantity you need. You can also ask for meat trimmings as that is the extra fat that gets cut off the cuts being packaged for the sales floor. There’s often a lot of meat attached to these, and you can get them cheap.
Freeze-dried food is nothing new. As early as the 13th century, the ancient Quechua and Aymara people of Bolivia and Peru pioneered a form of the process by exposing potatoes to the freezing temperatures of the Andes overnight, then drying them in the sun. In 1937, Nestlé used industrial technology to create the world’s first freeze-dried coffee, and in the 60s and 70s, the US military shipped freeze-dried food rations to the troops in Vietnam.