Hi,
1. It's quite easy to do. You need to use that code instead:
<?php echo hikashop_completeLink('order&task=show&cid='.$row->order_id.'&Itemid=XXX&cancel_url='.urlencode(base64_encode(JRoute::_('index.php?option=com_comprofiler')))); ?>
where XXX is the id of the menu item with the alias "my-orders". So like the search plugins or the modules of HikaShop, the solution is to have a "menu" setting in your plugin so that you can configure the id of your menu item to set it in that URL.
2. We'll be happy to add it to the integration documentation once you provide a finished version.
3. This would have to be much complex. First, we don't have such integration with anything else like that.
And the address edit form isn't meant to be embedded somewhere else.
Why not instead just add a link to your easy profile page which would redirect the customer to the addresses manager of HikaShop's control panel ?