Hi,
The tag {VAR:billing_address.address_title} will directly use the value from the database, without any processing.
So you can't use that.
You need to use PHP instead.
For example:
<?php echo JText::_('HIKA_TITLE_'.strtoupper($data->cart->billing_address->address_title)); ?>
For the end page, it's sure is possible too. But you'll need to customize the view file used there with custom PHP code. It will depend on how your checkout is configured, which payment method you're using and how you've configured it, so I can't give a precise answer without knowing that.