1) Based on your import template you can define unique keys from the following:
[*name
*username
*email
*seller unique code
*seller company name]
any of the above can be selected as unique as per your CSV to identify seller row.
If product Unique is already existing and Seller Unique is provided importer can also attach products to multiple sellers.
The importer can also be used to create new sellers, categories, products, variants, special categories etc if they do not exist in the system. All this can be configured in importer template.
2) Media can be imported in following ways.
[*By providing absolute URLs of the source ( can be any third website) in CSV importer will automatically import them from source. You have to run following
/index.php?op=sellacious.downloadQueue
to import the absolute images inside the system.
* By providing relative image URL by uploading them first in any folder and then providing relative URL.
* By Sellacious Media importer by any unique key example SKU etc to automatically link images to product or category
* By importing the Zip file of Images by Unique key example SKU or Product
]
Last Two are also applicable for Document Attachments too.
Learn more here:
https://www.sellacious.com/documentation-v2#/learn/import
3) Yes, if you provide any FTP to the seller and an import template you can run cron on regular intervals to automate it. Enterprise version we can automate this entire process.
-Abhishek
Team sellacious