After a few days tediously and relentlessly testing I managed to create a modified CC3+ character as a Cloth to apply physics. 
If you would like to see a simple Soft body Character Physics in iClone 8 please vote here https://www.reallusion.com/FeedBackTracker/Issue/Request-to-allow-Softbody-Physics-on-character-s-skin-influenced-areas-are-to-determined-by-weight-map-painting


I imagine a painting tool in iClone that you will be able to paint & quickly* test areas to influence more flexible areas of skin rather than create in CC3 then send to iclone each time - or at least just update the physics textures in iClone rather than sending the whole character over.
As a bonus, using soft cloth you can use little or no tessellation if you have a character that uses displacement in their skin to create actual physical bumpiness rather than rely on normal maps. If you want to see SkinGen get an update to support displacement texturing for actual deep bumpy scars, pores, wrinkles etc then please vote for it here https://www.reallusion.com/FeedBackTracker/Issue/Missing-Corresponding-Displacement-maps-of-scars-tendons-wrinkles-pores-burns-etc-Unsatisfied-Purchase 



Store Page Link 

AMD 4.5 GHz 16 Cores  | 128 GB | RTX 4090 | Window11 | Houdini FX 18.5 | Zbrush 2023 | Maya 2014 | Adobe CS6 | Sonar Producer X3 | iC8, CC4 | DTS Master Audio Suite | Perception Neuron 32 Alum Edition | Akeytsu