The most popular video claiming this is a hoax, argues that the parents of the dead children are actors, and no one died.
Which is disgusting, and all these people saying we don't know if anyone died of not...look, I understand your need for some kind of mystery, but get your head right out of your ass.
The reason people think this is a hoax, is because the news reported every single weird dead lead for this as it came in, with no fact checking and no waiting for more details.
So it all looked like a jumbled mess.
As far as a FEMA thing goes, they host those classes ALL THE TIME, and it takes two seconds of research to find that out.