Hi,
If you activate the "Add Product Code (mpn)" setting of the plugin, it will use the product code of each product as MPN.
Also, in the setting "Identifier exists" of the plugin, you can enter FALSE and it will do it for all the products.
The setting "Use products brand" will use the brand you already configured in each product if activated. Otherwise, in the "Brand override" setting, you can enter a name which will be used as brand for all your products.
So with all of these, you should be able to remove these errors without having to modify each product.