Redesigning Existing Meshes
I started out trying to just adjust the textures and see how that was looking. I made everything matte and removed any metalness and specularity, since I thought it took away from the stylized look. I also liked the toon shader effect and wanted to see about using that for my display of these.
But I think I still need to work on the textures, and to do that I think I need to add more sculpt information to the props. They've got mostly flat surfaces. I worked on the low-voltage station first, tweaking some of the parts and trying to make its silhouette more interesting.
I also recently had to re-texture the main character, so I'll probably try to use a similar approach to the props. For him, I used ambient occlusion in the diffuse layer, plus the curvature maps to add 'linework' basically to try to emphasize some of his sculpt information.