After several hours of experimenting, I've managed to get it partially to work and have the borders but textures are original colour!
In sketch fx this
gl_FragColor = vec4(vec3(mag), a);
I've replaced with this
gl_FragColor = vec4(front.rgb * vec3(mag), a);
But I still would like to be able to change outline colour as well as have it stay visible when objects of the same colour overlap as well as to be able to change it's colour. Which I bet is difficult to get for someone with no proper programming experience! But I'll give it a shot, and if I haven't written anything and you guys could help with that that would be ace.