Retopology and baking normals for double-sided (thick) clothes from Marvellous Designer workflow I apologize for wording stuff badly in advance.

I can't work out an efficient workflow for creating clothes with thickness using Marvellous Designer and Blender that incorporates retopology and texture baking. 

Currently, I have a project in Marvellous Designer with a character in a shirt and a coat. Coat is supposed to have thickness (so the insides could be seen).

My plan was:
1. Modelling and simulating clothes in Marvellous Designer, export without thickness (done)
2. Sculpting details in zBrush/Blender/3DCoat/Sculptris/whatever (done, used Blender and 3DCoat)
3. Retopology in Blender (done)
4. Apply thickness modifier to the low poly and high poly models (done)
5. UV low poly in Blender (done)
6. Baking Normal Maps in Blender or xNormal /maybe Knald or 3D Coat (tried xNormal and Blender - bad results)
7. Import in Unity/Unreal

But I'm having problems with #6 (baking normals): both coat's and shirt's collars project on geometry under themselves. As I understand, I'd need to explode the model (separate and space out all geometry that might overlap - in my case - collars from the shirt and the coat and probably the insides of the coat, too) but the thought of going into the edit mode for high poly models is terrifying, let alone trying to select something there (freezes due to high poly count)
Tried baking with cages - trying to adjust the cage for collars or other tight spaces or inside cavities seems next to impossible too.

So I guess, it's either of two questions:


Is there an easier workflow for clothes made with Marvellous (on what stage do I add thickness: when exporting from MD / to high poly sculpt with thickness modifier (looks bad) / to low poly model (baking one-sided mesh to a thicker topology?) ), how to retopo cavities under collars so the bakes there would be hassle-free? 
Or is there just an easier way of baking overlapping geometry?
This works to some extent:

Flip the normal of the inner faces
Bake the Object Space normal
Connect it in your material shader graph, even though your normal is in Object Space, use Tangent Space in your Normal Map node.
Create a new image, select it and now bake the normal map, but this time use Tangent Space.

If anyone knows the better workflow, please share it :)