I might need some screenshots so I can see what the problem can be, although if you're talking about the jitter with jigglebones you have to play around with parameters and to be fair I'm not experienced with them and I had to use some settings I found online when porting my own models over for the jigglebones, although length is calculated automatically, and I don't know if weight painting will try to help the problem
I had used some of the internet too because I didn't feel like testing it over and over until it was ok. I fixed the jitter with some angle constraints, I think it fixed anyway, and also got some toon lightwarptexture shaders on it too. The materials were a part of Blender's fault because when I put the model in Blender, it created a second set of materials that were auto-applied. I never go to the face posing to work, but that's ok
