In my workflow, I have 4 pieces together. HiRes, LowPoly Quads, LowPoly Tris, and LowPoly Tris Cage. I use Tris and Tris Cage to bake HiRes. Then apply the texture to the Lowpoly Quads.
And some shots of the wireframes and lowpoly with no diffuse applied so you can see the sculpt more clearly... Lowpoly - No Diffuse Lowpoly - Wireframes
yeah looking at the lowpoly, how straight the lines appear. i assume they built the lowpoly first, then used it to create the highpoly, not sure if it was actually sculpted or maybe just smoothed, baked and all surface detail is just done in a software like substance painter.