Vendors use the /vendor_dashboard/ for WC Vendors Free, and /dashboard/ for WC Vendors Pro. Easy as that. 🙂 No toolbar needed, it’s all contained within the page.
If the product data dropdown is missing, check your wp-admin > WooCommerce > WC Vendors > Capabilities and enable all of them, then test again.
Simple Auctions are not supported in Pro (yet), however you can do it if you like, you’d have to customize the add/edit product template included with Pro in order to add in all those meta keys and allow for the values to be entered.