1) Active Directory is a database based system that provides authentication, directory, policy, and other services in a Windows environment
LDAP (Lightweight Directory Access Protocol) is an application protocol for querying and modifying items in directory service providers like Active Directory, which supports a form of LDAP
Refer the below thread.
http://scn.sap.com/thread/1352756
2) you can also maintaiin Bo with the enterprise users, but it will be slightly difficult to maintain users due to password resets, disabled.
3) ref the below thread
