Automatic registration for anonymous node authors I need anonymous users  to be automatically sent drupal 'welcome' link  when they create nodes (it's required to enter email and to create login when creating nodes). So AFTER the node is created, the user can go on with registration.
I am not sure how easily you would be able to do this, but you might be able to do this using rules.  

Have a look at Inline Registration.  You can configure quickly to attach a registration form to the node creation form.