- WooCommerce
- Ultimate Member
- Paid Memberships Pro
It is unnecessary to use all of these. Since you are going to be using WooCommerce anyway, a better approach would be to use WC Subscriptions and/or WC Memberships which integrate well with the WooCommerce core. Additional layers from PMPro and Ultimate Member will only complicate things and reduce reliability.
Alternatively, consider Discourse Subscriptions and use Discourse as the SSO provider. If the benefits of membership are access to specific areas of the forum, then this would probably be the best solution and you wouldn’t need WordPress membership management at all.