Problem with the chromatophores. On starships, they are electrified to produce shifting patterns of dark grey on black, making visual identification nearly impossible. However, if one set up a primitive nervous system that directed the signal from retinal cells to the other side of the pack, and with improvements to the genome allowing a broader color arc, then yea, no problem.
They also wouldn't produce the resolution of a volumetric display, and be only about as effective as a camo pattern, but more adaptive to the environment. Like how OCP only really works in woodlands, and ACU was more for urban.
As far as how you put on a ruck... You flip the bastard so the frame is up and the top towards you, grab it under the straps, and flip it over your head, dropping it on your back and the straps over the shoulders. From there, tighten and clip your waist strap.