onBeforeProductupdate() Trigger firing

Indeed, the triggers are not called for the toggles on the listings of the backend.

Please edit the file administrator/components/com_hikashop/controllers/toggle.php and change the lines:
if(method_exists($class,'getTable')){
$table = $class->getTable();
}else{
$table = hikashop::table($controllerName);
}
$db =& JFactory::getDBO();
$db->setQuery('UPDATE '.$table.' SET '.$task.' = '.$db->Quote($value).' WHERE '.$class->toggle[$task].' = '.$db->Quote($elementPkey).' LIMIT 1');
$db->query();

to:
$obj = null;
$obj->$task = $value;
$id = $class->toggle[$task];
$obj->$id = $elementPkey;
$class->save($obj);

That should trigger the events for everything. Let us know how that goes as we would include that in next release if it works properly. On our end, it seems that everything is still working

Indeed. To handle that case, I think we could change the line:
$class->save($obj);

to:
if(!$class->save($obj)){
if(method_exists($class,'getTable')){
$table = $class->getTable();
}else{
$table = hikashop::table($controllerName);
}
$db =& JFactory::getDBO();
$db->setQuery('SELECT '.$task.' FROM '.$table.' WHERE '.$class->toggle[$task].' = '.$db->Quote($elementPkey).' LIMIT 1');
$value = $db->loadResult();
}

That way, the old value of the toggle would be reloaded if the save was not successful.

a/ Setting the do to false and the product_published to 0 is not the same. When you set the do to false, it means that the change is ignored so even if you put published to 0, that won't change in the database.

b/ In the Update events you can suppose that the data will be there every time. You should load it yourself in the plugin should you need it.

That's another problem indeed.
It's indeed a problem for both the products and the categories.

We'll modify that for next release as the solution is bigger to implement than just changing two lines.