Whilst we are going along the education route: mechanical seats have levers, bowden cables and pins into holes, all subject to wear and failure; electric motored seats, as far as I recall, all had a mechanical back up, not a B787 Engr, but from earlier posts of the mechanical selection cutting out the actuators suspect the same back-up.
2 switches? the button switch had a very positive feel, also pilots might select the directional switch and then blip the button switch, hence failure would be apparent; blip-ping the directional switch is much more subject of incorrect direction.
When I first worked on an American aircraft of BAE manufacture, I questioned the foot rests on the instrument panel; I was told used in cruise, I note not visible on the B787 panel, but I would still suspect Pilots sit at the rear most seat position during cruise, than hunched over the control column, perhaps some actual Pilots might comment?