Another potential issue I have: I have a file called FCOM_KDCircletsOOOOptimizedNPCEquip.esp and another named KDCircletsOOOOptimized - Loot Only.esp. Do I want both of these or is it like the Runeskulls where I only need the FCOM file?

Remove the Loot Only plugin. That FCOM plugin is a patch for the other version. (See http://sites.google.com/site/oblivionpoinfo/lists/myloadorder.) There are instructions about adding the other KDCirclets plugin in the FCOM bashed patch, a subpage of the main "Bashed Patch" page.