Personally I let one year olds just be one year olds. They get enough sensory, tactile, etc from interacting with the environment and do not yet have a creative side so to speak. Being creative is based on knowledge and experience. Do not be in a hurry to rush one year olds to do organized activities. Keep everything very open ended. The fact they are eating the crayons tells you that they have not reached the maturity required for the activity. This is especially true if you have them in their high chairs. An orange crayon looks like a carrot stick. How are they to know the difference.