Should work on any part of forumhome that uses the $lastpostinfo variable. Sorry, can't say why it wouldn't work with Xenon's Hack.
For the moderator name, it would be the same thing. Find:
PHP Code:
$showmods["$moderator[userid]"] = true;
Above that add
PHP Code:
// Begin Username Truncate Hack - vBMechanic
if (strlen($moderator['musername'])>18)
{
$moderator['musername'] = substr($moderator['musername'],0,18)."...";
}
// End Username Truncate Hack