How about creating custom WordPress login page using
<?php wp_login_form( $args ); ?>
Place on the page template the title you wish and the site information then call the login form.
Alternatively(I have not tested this!) adding information in the form area by passing the information you want to add in an array. It will look something like :
<?php
if ( ! is_user_logged_in() ) { // Display WordPress login form:
$args = array(
'redirect' => admin_url(),
'form_id' => 'loginform-custom',
'label_title' => __( 'Site Title' ),//Displayed in the login form
'label_username' => __( 'Username' ),
'label_password' => __( 'Password' ),
'label_remember' => __( 'Remember Me' ),
'label_log_in' => __( 'Log In' ),
'remember' => true
);
wp_login_form( $args );
} else { // If logged in:
wp_loginout( home_url() ); // Display "Log Out" link.
echo " | ";
wp_register('', ''); // Display "Site Admin" link.
}
?>