For color, my recommendation would be to go with black. I see the blue you're talking about on the images above, but I think that's just a reflection of the game.
. . .
My next recommendation was to go with whatever the Darktrooper from Battlefront I and II had in terms of color. This is because that's the most consistent singular source image out there of any of the variants, and since whenever they're together in reference images they all seem to have the same color, it would be a good idea, in my opinion, to keep it the same across the board or at least near the same in terms of color. Hence the idea to go with what the Darktrooper has.
However, apparently it's been longer than I think since I've played Battlefront, because looking at images, the armor is clearly a gray on that one. Whoops. Anyways, in terms of color, my recommendation boils down to that: keep it consistent amongst the variants, starting here. But I'll go on ahead and let others weigh in on that.
- Master Tej -