At some point you might want to include additional checks for enabled modules, specifically the Friend/Foe functions, and hide/display all references to them depending on status of the module. In addition to the wonderful progress made here , you should also remove the filter from the UCP -> Private messages -> Rules where you can still define a rule based on 'is friend' or 'is foe' regardless of the modules being disabled. Nothing earth shattering just a consistency issue.

Also while I am at it, at some point perhaps you can think about following this concept through to the default FAQ page as well, providing a check to see if a specific module is enabled or not before displaying the FAQ section for that feature, i.e.

Friends and Foes
What are my Friends and Foes lists?
How can I add / remove users to my Friends or Foes list?

It would certainly be a lot easier for Admins who disable certain features on their boards to not have to manually edit their FAQ pages to remove reference to a feature not available.