It may seem silly, but I want to edit out the post-registration "login form". Where can I delete that "event"?
You can't 'delete' an event, but you can make changes to its functioning. You can use the xtralogin sample plugin as a model. There is a register output event, where you can add a hidden input and check for it in the login form event. If it appears when the login form is accessed, you can set the login event to array(). Then the form will not be printed. You will still get the not logged in message, I haven't checked on how to by-pass that.