Does UNAB require CAeAC or vice versa?
There is no requirement for CAeAC (PIM Endpoint) to be on the same server as UNAB. There are features that can be enabled if both products are installed on the same server. There are no requirements in UNAB if you uninstall PIM from an existing install. The features for interoperability are more on the PIM side where AD login names can be used in PIM logs and PIM can use program rules to protect the uxauthd binary.