I’ve heard of motifs before, but I thought they referred more to general things that are in different stories but tend to represent the same thing, like a wise old man or a ghost appearing. Maybe I’m getting it confused with archetypes.
The Scarlet Letter has a ton of symbolism and motifs. In one of my favorite books, The Eagle of the Ninth, there’s a wooden bird carving the main character made when he was young, a spear decorated with heron’s feathers, a Celtic shield boss, and of course the Roman eagle standard itself. They all appear at key moments in the story and probably do have a symbolic meaning as well (e.g., the carving represents the MC’s childhood, the shield boss shows the difference between the Celts and the Romans, and the standard symbolizes honor and duty, etc.) Gary D. Schmidt also seems to have motifs in his books as well, as well as a lot of repeating phrases that I always find really cool.
I hadn’t thought too much about putting motifs in my books, but I’m sure they would naturally come up. I like your idea of each character having their own “look” with certain colors.
"For He knows our frame; He remembers that we are dust." - Psalm 103:14