I started this project a few months ago and it was a fantastic learning experience. It was great to practice the general process of creating a realistic character.
I used Zbrush to do the modeling, Autodesk Maya was used for retopology and uvs and the textures were done in Mari using a Multi-channel Faces kit from the XYZ website. I set up the shaders using Mari's textures along with some auxiliary maps that I exported from Zbrush in Autodesk Maya using Arnold as a renderer.
That's it, thanks!