No. It extends Cycles with OSL nodes and some python nodes to implement NPR features.

No. Since OSL shaders are CPU only. Toonkit does not support GPU rendering.

Lightning fast! You just less than 16 samples to make a production-quality image without denoise. We provide many presets of quality that you can control in the Toonkit Settings in the render panel too.

Yep! It support Baking for most of the nodes. The golden rule is that view dependent can produce some unexpected results. Line Rendering of course don't make sense in bake.

There are two known limitations for the line rendering node. They don't work with Orthogonal Cameras only perspective and you need to enable Clamp and set up a good value for it to make it work through transparent objects.

Yep! It's compatible with the latest blender verions