wp_mail BCC admin

$post->post_author will return the ID of the post author, which you can then use with the WP_User object to retrieve the username and add to the outgoing email:

if (get_option('jr_bcc_apply_emails')=='yes') :
  $author = new WP_User( $post->post_author );
  $username = $author->user_login;
  $to = get_option('admin_email');
  $subject = __('[copy] going for "', APP_TD).$post->post_title.'"';
  $message .+ " {$username}";
  wp_mail( $to, $subject,  $message, '', $attachments );
endif;

Codex: WP_Post

Codex: WP_User