How do certain items sync or not sync back to Epicor Eagle?
The best answer is to contact Epicor Eagle to answer this. They control their inventory, and we cannot change it.
It is possible to define whether the inventory updates from Epicor Eagle are synced to the WooCommerce integration by checking/unchecking the manage inventory box in WooCommerce. For more information on that, please refer to this support article about configuring existing products in WooCommerce.
Any order placed on WooCommerce will be sent to Epicor Eagle. All products on an order get sent to Epicor Eagle. Modern Retail sends the orders exactly as we get them from WooCommerce.
How Epicor Eagle handles those orders is defined in the Epicor Eagle integration. We can not differentiate items.
For any other questions, please feel free to submit a support request in the Admin Panel.