Ok, watched the video up to the point of the "caskets" inserted video, then I watched that. I will watch the rest of the video after Christmas, but up to where I watched it so far it has a conspiracy theory type feel to it. I'll comment on the rest later, but after 5 minutes of searching on the web this is what I came up with for the "caskets".
Check out this link:
http://www.casketdiscount.com/vantage%20vault.html (
http://www.casketdiscount.com/vantage%20vault.html). the second burial liner down looks a lot like the things FEMA has piled up. Depending on where you live in the US you may legally have to use one of these when you bury somebody
in a coffin. They are meant to go around the coffin to keep the ground from settling above it, and can be lidded as you see in the video if needed to prevent contamination of ground water. The lid would go on the bottom in real life use. It would be easy enough to seal with a good polymer.
There are plenty of legit reasons FEMA could be stockpiling these. The easiest I can think of is superflu or a biological/chemical attack that kills lots of people quickly. You don't want the bodies lying around or it could create a secondary disease vector, so you'd probably want to put them in the ground as quickly as possible. In a crisis situation I could easily see them burying 2-3 people per liner with the intention of allowing relatives to claim bodies after the crisis passes. As an added bonus they are plastic and sturdy so it is unlikely that you would have a problem with ground water contamination (witch is actually their primary purpose).
I got no answer about the camps/trains/armored cars right now. I'll watch that bit later.