Hi,
1. You can edit the file "show_default" via the menu Display>Views and change the line:
echo JText::sprintf('MANUFACTURER_URL', '<a href="' . $this->element->product_url . '" target="_blank">' . $this->element->product_url . '</a>');
to suits your needs.
2. The warehouse system in HikaShop allow you to group products into different shipping groups to be able to offer different shipping methods for different shipping groups. That way, you can have multiple shipping methods (for different products of the order) in the same order. That's similar to what amazon does when you purchase products from different vendors.
The goal of the brand URL field is to be able to link to a specification PDF or page from the manufacturer. For example, if you sell an Acer laptop on your shop, you might want a link to the specifications page of the laptop on the acer website.
3. Yes, I think that this suggestion is the easiest to setup
www.hikashop.com/forum/product-category-...re-a-way.html#200166
to remove the add to cart button for some products.