Answers
-I'm not sure about brown eyes yet. I can't decide if they should have a power or not.
-I think the majority of the people would be darkeyes with a minority of say 20% of people in the world being coloreyes.
-There are different eye colors on this planet than earth. For example, yellow, red, orange, purple, white. I'm thinking something like a color wheel where you choose a color (on photoshop for instance and there are 2-4 sections for each color depending on how you define them. There is a vibrant of each color(water moving,in the example), a pale of each color(water freezing), and an inbetween color for each side of the circle, if that makes sense. So blue has vibrant, pale, blue green, and indigo. Purple would have vibrant, pale, indigo, and maroon. Etc. the central colors are blue, purple, red, orange, yellow, and orange. There is also white, but there are no shades of that.
-Colored contacts are a smart idea and would probably have been used on this planet
-The gold thing is interesting, I'm not sure about it.
-I don't understand the last one