Our software doesn't track wrist/forearm twists from cameras. It's possible to track wrist rotations using
motion controllers. Rotation is applied to wrists (LHand/RHand joints) which usually works well with models having long-sleeved clothes. There is no option to distribute twist rotation between wrist end elbow. Probably this can be done in your animation software.
There's a detailed comparison of various camera configurations in our docs.
http://docs.ipisoft.com/Multiple_Depth_Sensors_vs_Web_Cameras_vs_Action_Cameras_ComparisonIn short, RGB cameras provide the best accuracy with proper setup (camera positions, lighting, actor clothes).
We do not have experience with USB controllers in AMD chipsets. Thus I cannot tell for sure. Also, this depends on camera model and video mode you will use. Speaking of PS Eye camera, I think you'll be able to use at least 4 items at 60 fps or 6 at 40-50 fps. Unless there are compatibility issues between camera and USB controller.