If you want to know what some of the ingredients for the cakes are or where they are bought, then this is the place with the answers.
Icing colors is very concentrated color for food. It has no taste and the color is so concentrated that you only have to use a few drops at the time. Personally I just toothpicks to take small drops with.
I use some made by Wilton, because in my experience they are the best ones. They can be bought in a huge variety of color and can be mixed.
Spray for cakes:
Can be bought in gold & silver (and perhaps also in other colors) and it’s edible. Cover around the cake and open a window when you spray. Let the cake rest for a while and it’s ready. The gold spray I used is made by Wilton.