Hello Dan.
I am happy to assist you today.
The backorder setting in Woocommerce is supported by WP-Lister.
With the backorder setting enabled, when a sale takes place on WC or on eBay and the stock reaches 0 (assuming you are using Pro so WP-Lister can reduce stock when a sale takes place), the product in WC will stay with a status of “In Stock” and users will still be able to purchase the product on WC. By default, Woocommerce will show “Out of stock” when stock reaches 0 (that is assuming the backorder option is disabled).
If that doesn’t exactly answer your question, could you please clarify what else you are asking about?
Thanks!
John