Set up all users and Groups in AD first, assign Users to matching PWA Groups then do Resource Pool Sync then User Group Sync. The User Group Sync populates this data in EPM.
Under Organization Tab in AD, fill in Department because it maps to Group in PWA and Fill in Manager Name because it generates an Org Chart in SharePoint Profiles Service. Resource Pool Sync is the sync that populates this data in EPM.
Generic Resources can be entered in AD and used to create the Generic Resource in EPM but you must turn off Allow AD Sync before setting to Generic.
Create a Skill Look up table and enter in the Generic Resources as the Skills. Create 2 fields for Skills, one for Primary skill (not multi select) the other called Skill Other (secondary skills) make it multi select. Reason being is that multi select fields do not show in Cubes. To do analysis in cubes of generic resources you will have to tag tasks with Skill as well maybe. Need to look into this.