As this happened in June, and White Star Line states the officers and Captains uniform wore white uniforms during Summer, it is likely the officers. as Murdoch was (originally) Chief Officer and then on the bridge, then Lightoller who was (originally) first Officer is then the man at the bow.Not sure who the 2 men dressed in white uniforms are on the bow. There are 2 more on the stern. Could they be the ship's officers?
So you could see a little sliver the whole way of the ship? Just a little? This is the picture I am looking at:Don't know what picture you are looking at but you are describing what is called a 'boot-topping line'. As far as I know, Titanic did not have one. The underwater part of her hull was painted in a red-anti-fouling paint. This was continued above the light displacement level to where it met the black part of the hull paint.