Individual survivalist preparedness and survivalist groups and forums—both formal and informal—are popular worldwide, most visibly in Australia, Austria, Belgium, Canada, Spain, France, Germany (often organized under the guise of "adventuresport" clubs), Italy, Netherlands, Russia, Sweden, Switzerland, the United Kingdom, and the United States.
Mylar emergency blankets are great survival gear but sometimes you need more than that. The Coleman North Rim Extreme Weather Bag will keep you cozy warm when the air temperature is 0 degrees Fahrenheit. In temperatures like that you can lapse into hypothermia quickly especially if you’ve been slogging through the woods all day and are sweaty. Just crawl in the North Rim bag and pull the drawstring to lock in the warmth. The cover is durable rip-stop nylon so you can lay it on the ground if need be and there are snag free dual zippers so you can get in and out quickly and easily. Must have survival gear for winter adventurers.
Each type you listed (save a couple) will have its uses in a community (group if you will), generally having a small trusted group with each having several skills in the various fields (prepper, homesteader, and survivalist) I believe would be an effective team, though as each group works together would it not be best to ensure that each has overlapping skills in case of injury, death, or other reasoning they can not fulfill their duties?
Modern-day survivalists aren't generally regarded as the most sane people on the planet. A quick look at any one of the disturbingly common and frighteningly thorough shopping lists they post online drives home the fact that anyone who self-identifies as a "prepper" most likely went off the deep end a long time ago. Sure, it's fine to keep a few extra cans of food and cases of water around for an emergency, but if you start adding body armor and butt paste to your stash, you might want to tell George Miller that it's time to see other people.
To me, the best option is to store emergency food. How much? If you have none, store enough for a few days. If you have enough for a few days, get enough for a week. How much you store depends on what time frame you think you're at risk for having to be completely independent. The early settlers of the southwest liked to store enough food for a whole year and still do to this day!