As I understand you do not care about the character and only want to combine the outfit (otherwise see animagic's reply )

There is a way for doing that and you have to use Blender pipeline.

Given you already have set hidden faces for clothing items (layered clothing for instance) and would like to delete those faces permanently and combine cloth items.
So before the export you have to select each cloth item, go to Hide Body/Mesh Tool and select Show All.
That would ensure that not a single face from the character itself would be deleted on export from CC.
Next export with pipeline and check Delete Hidden Faces
Import to blender with Pipeline add-on and for each cloth item use Mesh > Clean up > Delete loose (CC only deletes faces on export leaving a bunch of loose vertices).
Then in object mode select all cloth items with Shift and use Ctrl+J to merge (weight data would be preserved).
Export from Blender and import to CC (again with pipeline). On Layers selection prompt, combined cloth might be selected as Hair by default. Make sure to choose Cloth option.
Done.
Weights and Materials for merged cloth would be preserved. Just make sure NOT to merge dissimilar items like Cloth with Shoes and/or Gloves.