Look at your Diffuse (Base Color) Textures only and run a histogram analysis in Photoshop and you will see that they all do favor either a yellow (toward green), orange or white/grey-ish color.
You can adjust the textures themselves or pull out the greyscale image and adjust the color via a lerp &/or Mulitply with one or two 3 Vectors. In either event, you will get these results:
Eric Ketchum