Hi,
1. The text inside the parenthesises is not the email address but the username of the user account. It seems that the email address has been used as username for that user account (or maybe the website is configured to always be like that), which is why it looks redundant.
2. Yes.
In both cases you can edit the file "order" of the view "dashboard" via the menu Display>Views. There, you can change the code:
if(isset($row->user_cms_id)) {
$customer = JFactory::getUser($row->user_cms_id);
if(!empty($customer->username) && !empty($customer->name))
echo $customer->name.' ( '.$customer->username.' )</a><br/>';
}
$url = hikashop_completeLink('user&task=edit&cid[]='.$row->user_id);
echo $row->user_email.' <a href="'.$url.'"><i class="fas fa-pen"></i></a>';
for the name of the customer, and you can add a new column to the HTML with the date that you'll have with hikashop_getDate($row->order_created);