AEC Collection contains AutoCAD and CADmep. CADmep requires AutoCAD or other AutoCAD based product to run as.

Revit references the same database configuration as the Autodesk Fabrication products but base Revit has that functionality built in so there's no other products you need. Again, Revit is also included in the AEC Collection.

ESTmep and CAMduct are not part of the AEC collection. They don't need any other products to run.

To manage a Fabrication configuration at this time at least 1 person in your company will need CADmep, ESTmep or CAMduct to be able to manage the database.