I'd recommend taking the time to break down, with a 2D paintover, the planes of the face on Michael B Jordan. I recommend the Asaro head as an example of how that should look.
You can bend Speedtree to your will, by substituting the leaf meshes with your own branch-style textures, or even substituting them with the meshes from your 2nd example.
Also, you can make UV-pieces really small if no one will even see it, for example back part of wardrobe or/and top and bottom part of wardrobe, something like that
This would be a the best topology in this case. The closer a triangle is to equilateral, the more optimal it is. Your second example would still be triangulated to similar shaped long tris as the fan topology.
Here's a practical example of the above applied to blendshapes : https://www.youtube.com/watch?v=BUG3QwRjABY&feature=youtu.be As said this also works for skinweights, vertex color data, and so on.
A simple example would be to plug a shape into a distance node and that into a normal node If you set the distance to 10 and the normal intensity to 10 you'll get a 45degree angle (at 2048)
Looks extremely good, but why don't you use metallic for all metal parts, like the gun metal of the barrel for example (trying to better understand PBR myself)?
like this for example: http://www.ebay.com/itm/Acer-Aspire-ONE-A150-Netbook-ZG5-White-w-broken-Screen-/270912432652?pt=Laptops_Nov05&hash=item3f13a3aa0c#ht_500wt_1287
Note: This is a good example of my horrible thinking process. I wasn't thinking about the bigger picture, perspective and I avoided many things out of fear of failure.