It's all look pretty much like CelShading Toon Shading (you can google both and how it works.) with flat colours. In Arnold you have basically there a slot for Diffuse Flat Colors and can readjust color of the Shade that works something like on the screenshot. Shade color also can be connected to the diffuse color with…
I'm fairly sure it must be using a world space map when baking low-low in substance - you'd get an empty texture otherwise. iirc you can composite a tangent space normal into that at bake time as well so i think that covers what you're asking for. since you mentioned the sobel/seams interaction .. yes - that hadn't…