Hello,
In the email "preload" part you will see a loop on the cart products.
foreach($data->cart->products as $item) {
You have access to "all products" (content from the HikaShop product table) in the variable
$productClass->all_products
The idea is to get the vendor_id from the products (best is to take the first $item and get the content from all_products).
Once you have your vendor id (in "product_vendor_id" field) you can load the object object via
$vendorClass = hikamarket::get('class.vendor');
$vendor = $vendorClass->get($vendor_id);
And access the various fields such as "vendor_name", etc.
Regards,