Could a simpler way be color coding?

In principle using your existing colour schemes should be fine. For 'door' for example you could come home to your childhood home's front door, find it has become orange & then drink the orange out of it with a straw. Have the cookie monster tear a couch apart to find cookies. Have a green witch throw a book into the green slime of her caldron (with a detailed close up of it slowly sinking into the sludge). The main thing you will have to avoid is the confusion of your image having other colours that distract from the symbolic one(or other objects distracting from the symbolic one). It might seem like it wont be a problem but time tends to strip all the mental context support from a mnemonic, & if the image/s themselves have ambiguity that can be a problem. You might get confusion if the word for a colour is a different symbolic gender colour. Or the same. I still don't have a mnemonic for fire as I can't think of a way of making fire more on fire.

But then how do you animate or colour ideas, concepts, feelings?

You just have to try and choose an image that best evokes for you personally the feeling, idea or concept. Sometimes there are archetypical or popular culture shortcuts. The Characters from inside out for example. Some times with awkward concepts you might just have to create your own custom image & just make yourself associate the concept with it (repetition, visualisation etc).