Oh, right... "user", not "name". I keep forgetting which menu has which property name... And yeah, I used single quotes when I should've used double (which would've created a few new lines in the output), sorry.
The "/ip hotspot user" menu is for all users (and that's where the property is called "name"), while "/ip hotspot active" is for all "active" (as in, "logged in") users. If you're trying to read data from there, that's the only menu you should be reading out of. The limit-bytes-out should be readable from there if you add the "stats" argument, i.e.
$activeUsers = $util->setMenu('/ip/hotspot/active')->getAll(array('stats'));
//Display the username and limit-bytes-total of each active user
foreach ($activeUsers as $user) {
echo $user('user') . ' - ' . $user('limit-bytes-total') . ";\n";
}
(or if that doesn't work, try to replace "stats" with "detail")