1. the back of the calf cuts through the cloth

Character skin can have displacememt map, or you need increase collision detection and offset. "Smooth polygons" in render setting can cause problem or resolve it ;)

 

2. the sleeves look crumpled with a wavy appearance on part

It must happend if facets have more then 3 vertex. Triangulate in modeling program or UV Mapper. (Pro)

 

3. Some bits on the skirt area show the facets of the model. It is terrible and visible even with fur material.

Open obj in UV Mapper.

Select all.

In "Tools" menu select "Normals" => "Smooth"