How can I change the page title for user/login for unauthenticated users?
You have alot of good information there (seriously). What you want to do is probably use hook_form_FORM_ID_alter() on the user form.

You want to set the #title attribute of the form element for the name element of the login form.

Some example code:

function MYMODULE_user_login_form_alter(&amp;$form, &amp;$form_state) {
  $form['name']['#title'] = 'Your Nickname:';
}


You'll probably want to check that a user is not logged in yet with something like user_is_logged_in() or your own custom logic.