Nice approach - programming + art in one))) Excellent idea!
I would like to ask you two questions:
1) About Mobile support. As I understand problem is in Shaders? Will be OpenGL ES 3.0 enough (SM 3.0)?
Can I make mobile support by myself or shaders require SM 4.0?
2) Auto-retopology is available on Windows. - I am right that you are using C++ library?
Retopology is only to reduction vertices/triangles or doing anything else?