Hello,
I have configured OAM PS3 (11.1.2.3) with Facebook. OAM PS3 admin guide was followed for this implementation. The use case is as follows:
1. A user accesses an OAM protected resource and is prompted for authentication (by OAM)
2. User selects "Sign in With Other Account" (Facebook).
3. Post FB authentication, user is redirected to OAM registration page (/oic_rp/register.jsp) as the user record doesn't exist in local OAM LDAP.
Issue: FB only returns "id" and "name" attributes for this user. The OAM registration page only displays "id" and "name" attributes from FB. Other user profile attributes like "email", "first_name", "last_name" are blank.
Notes:
1. The FB app (configured in developers.facebook.com) has been configured with the following default permissions:email, public_profile (first_name, last_name) and user_friends. 
2. When OAM, internally, accesses the URL "https://graph.facebook.com/me?access_token=......", the response is 
{
  "name": "John Smith",
  "id": "45637283957563525"
}
3.  I have tried 2 different FB accounts but the results are the same.
4. The site URL, in FB app, has been set as "http://<OAMHost>:<OAMPort>/".
5. The "Valid OAuth redirect URIs" has been set as "http://<OAMHost>:<OAMPort>/oic_rp/return"
Has anyone seen this issue before? Any help will be highly appreciated.
P.S.: OAM is configured with DCC tunneling enabled due to other business use cases. The web server on which DCC webgate is installed acts as a reverse proxy to "oic_rp" URLs.  Just FYI.
Regards,
Sriram Ravikumar.