I stopped to use Zbrush couple years ago and it starts to evaporate from my memory. Did new versions got some way to fill in matching displacement and color from a pair of color/height textures in selected areas only ?
Use projective painting or noise dialog to paint color and depth from a texture in sync? I recall I did it with noise dialog somehow but can't recollect now. Maybe it wasn't zbrush , rather 3d coat although .
Still would be appreciative for any trick how to do it in Zbrush