Hi,
You could simply enable the breadcrumb module of Joomla via the Joomla modules manager so that you would be able to easily come back to the listing and that would also allow the customer to know the category of the product while still being on the product page, so it's even better. Even more so that on the pagination area, the current page link is not clickable so you wouldn't be able to go back to the listing if you were to put it on the product page.
To remove the coupon field, you can remove the "coupon" view from the "checkout workflow" setting of the HikaShop configuration.