Display all existing members

You can use get_users().

$args = array(
    'fields' => 'all_with_meta',
);
$users = get_users( $args );
foreach( $users as $user ) {
    // your display code here
    var_dump( $user );  // so you can see what's in $user
}

all_with_meta will get the user and all the associated meta, if I’m reading the Codex page right.

Update: After testing the code, I find that 'number' => -1 returns nothing at all, so I removed it from the code.

Reference

• get_users()