What is the relationship between OpenLdap and Novel eDirectory?
I don't think there is any besides the fact that both implement LDAP protocol.
Novell implemented an X.500'ish complaint directory, called NDS (Novell Directory Services) years ago in Netware 4.0 (early 1990's). They have upgraded it over time, and added an LDAP layer to it, since it predates LDAP's creation.
With later releases they renamed it eDirectory, and it has grown and matured. The LDAP module is much more tightly integrated, to the point where it is mostly indistinguishable. (Though it can still be unloaded). Amusingly, there are some things you can only do via LDAP that cannot be done any other way. Like modifying base schema. It can only be done via an LDAP delete and add in the same operation.
Some of the utilities Novell uses, suggests you use, and so on come from the open source OpenLDAP project. However, most anything that is LDAP complaint should work fine.
Thus I would say the relationship is one of shared ideas and notions, and possibly utilities, but not much else, between OpenLDAP and Novell eDirectory.