Question:
What AD requirements need to be in place in order for the UID from Active Directory to be read by Centrify and used as the "UNIX Attribute"?
Answer:
When creating a new Zone in DirectControl Console / DirectAccess Manager, there is an option to choose a schema Zone type. An SFU Zone type will get the Unix user data from Active Directory.
SFU Zones stores Unix user data in the AD user object.
Standard Zone is 2307 Zone and Unix attributes are stored in Service Connection Points objects in AD.