>Allow some customers to store their credentials in our IdP
Gluu allow you to maintain local user accounts in its internal LDAP server, and use them to authenticate users. This auth method can coexist with other auth methods Gluu Server supports. The main question here is how do you plan to add those local users. Gluu provides some simple user registration and management features, but it may not be enough for a serious production setup relying heavily on those features.
>Allow other customers to authenticate with their internal credential store using LDAP, SAML, or OAuth
Gluu Server supports a variety of authentication strategies, you can see the full list of them in "User authentication" section of [the docs portal](https://gluu.org/docs/ce/3.1.6/). That includes SAML and oAuth/OIDC authentication against some external IDP via inbuilt Passport.js module.
>Allow other customers to authenticate using social media credentials
Should be possible via the Passport as well (Facebook is supported, at least).