Why are the R, G, B lights different in terms of the representation format in those two screens (In iPhone 6S, there are strips; while in Galaxy S5, there are dots)?
It looks like there's actually a family of patented subpixel matrix schemes called the PenTile matrix family, and the Galaxy S5 uses this. It seems to use biomimicry to reduce the number of blue subpixels since S cones responsible for perceiving blues are lower in number in the human eye. This doesn't seem very evident in the image above though.
why are (or at least why does it seem like) the green screen pixels much smaller than the blue or red?