You may be able to use "root" models inside your new module, but I think it causes dependence.
How do you use these models? Try to import them when is necessary.
You can’t do the same with your “root” controllers. Each module must have it’s own controller. If you know how to use CAction, you may be able to create actions in separated class files and import them inside your controller.
class DefaultController extends Controller
public function actions()