In Revit, you can “fuse” families by loading a family into another one and create a combined geometry.

Such families are uploaded successfully into ALICE; however, they lead to complexities and miscalculations that result in inefficiencies in a project set up.

• The nested components have a somehow “independent” nature i.e., they can be selected individually in the model.
• They result in misalignment between the geometry in the model and the element data under the tree list as their nested components do not appear.
• Mesh Analyzer does not calculate the supported by relationships for those families.

On the above basis, it’s recommended that the use of nested families is avoided during the CIM development process.

To align with the scope of the project some elements can be removed. For example, if you want a door in your detailed schedule, you can remove the Doorknobs from the family because they don't contribute to the schedule detail. A simple door frame would suffice for the schedule requirement. (Image 1)

Revit families can increase the size of the project drastically. If the family element has curved details, it adds up to the polygon count. This should be avoided and remodeled with poly-lines. 

Image 1 - Simplifying Revit families by removing doorknobs from the door family

NOTE:  
It's strongly recommended to avoid using DWG components in the CIM model. All the DWG components should be removed or hid before importing the model to ALICE.  (Image 2 )

Image 2 -DWG component in Revit