Skip 1 and 2.. They are already crooks so why would they listen to your threats??
Go straight to 3 and 4 and move on..
Also, #1 has never been a successful method of doing anything since it is so easy to fake..
http://www.copyrightauthority.com/poor-mans-copyright/
If you intend to sue hire a lawyer and let him gather the evidence in a manner that will be supported in court..
Steve