all-users-page.php

<?php
/*
Template Name: All Authors' Page
Description: Get all the WordPress user's meta_information sort by the latest post action. (Which had at least 1 post published.)
*/
?>
<?php get_header(); ?>
<ul>
<?php
// offset -> post number | -1 means all the posts.
function get_latest_post_authors($number = 10,$offset = -1){
	global $post;
	$args = array( 'numberposts' => $offset);
	$authors_id = array();
	$myposts = get_posts( $args );
	foreach( $myposts as $key => $post ){
		setup_postdata($post);
		if(count($authors_id) >= $number) break;
		if(!in_array($post->post_author, $authors_id)){
			array_push($authors_id,$post->post_author);
		}
	}
	return $authors_id;
}

foreach( get_latest_post_authors() as $key => $author_id):
	$author_meta = get_user_meta($author_id);
	// get what you need.
	// var_dump($author_meta);
?>
	<li>Nickname: <?php echo $author_meta['nickname'][0];?></li>
<?php
endforeach;
?>
</ul>
<?php get_sidebar(); ?>
<?php get_footer(); ?>