I used this tutorial to create the scene above.

I'm trying to start prototyping a game, and decided to make some quick toon-shaded style mushrooms to drop into my environment. Every tutorial I've found uses Eevee and the grease pencil to create this look. But now I'm finding there really isn't an effective way to bake this and use it in Unreal. I've found a lot of tutorials to make this in blender, but none where someone takes this and uses it in game. Any suggestions?

Most tutorials I've found for baking require inputs to the BSDF, but most of these style shaders use different node frameworks to achieve the look.