The black areas with porcelain are most probably flipped patches. Sometimes it's hard to see. I like to set the option to render only one side of patches. Also there is a way to unify the direction of patches in the "right click" menu. Finally, sometimes you have to save the project and re-open to see the black patches are gone.
To your questions:
1. Not sure. Maybe the render to file option would fix this.
2. Are you sure you're rendering the right frame range? And there is a light right?
3. Could be Opengl/Directx related. Update any drivers and/or switch between the two.
4. Can't find the thread, but basically you turn on the "floating menu" then select a piece of the spline and press /(or is it ,) then in the floating menu you input 0 to the x fields. This is from memory, so it's probably flawed...