I know that this post is old. But if it helps you, for pixel art painting in substance painter you can use the PIXEL8R paid plugin by ActionDawg, it is very versatile and you can even make pixel normals with it. A lot of games are currently using it.…
Next prop I made for practise. Modelled in Blender, textured in Substance Painter, rendered in Marmoset. Please give me some feedback :) https://www.artstation.com/artwork/L28D5r