1. Flex Pass usage data is automagically captured in WooCommerce as a use of a coupon, a breakdown of the data model can be viewed in the New Data Model sub-section of the The Flex Pass Redemption Entity section of the Flex Pass and Related Entity Mapping documentation.
  2. We should validate that the purchase of a Flex Pass does not need to be modeled in CiviCRM in order to display use count in CiviCRM i.e. we can just get it via an API or something and display it in a custom tab or other appropriate container.