As a practicing lawyer for the last 30 years (if I practice enough I'll get it right) I have to jump into all of this wild speculation.
 
1.  This is America.   Anyone with a filing fee and the ability to sign his name can sue anyone about anything.
 
2.  The legal standard in any lawsuit over an airplane accident is whether the defendant's negligence (if any) was the proximate cause of the plaintiff's injury.  A jury gets to decide.
 
3.  I am not aware of any case in which the builder of an experimental aircraft has been sued as a result of a crash of an airplane he sold to the plaintiff.
 
4.  You can get hit by a meteorite at any moment.  Get a life.