All of these messages are examples of e-mail hoaxes. The sad thing is, forwarding hoaxes is not harmless. It is not just a matter of filling e-mail boxes and networks with useless junk. Hoaxes create enormous problems for the people who are the subject of the hoaxes. Hoaxes slander real people and real businesses.
Hoaxes cause real police departments and others to have to deal with thousands of concerned callers.
All hoaxes are forwarded by persons who don't realize how their good intentions are only making things worse. In my experience, there are very, very few legitimate messages which advise forwarding to everyone. But in every legitimate case, the subject of the message had already been widely reported in the media and other channels. And usually, even the legitimate messages can include technical errors or other factual problems. So, the world won't come crashing down if you simply delete messages asking you to forward it to everyone in your address book.