I would use this costume for the caterpillar, It brings together the character well. Even though the caterpillar is supposed to be blue, I would change his color scheme a bit and make it pink. Much like the cheshire cat, but they are completely different characters.
This would be the costume of the Mad Hatter. The Mad Hatter is my favorite character in the whole production. He is strange and hilarious at the same time. This costume says that as well. The goofy personality is represented with bright colors. The makeup is bold and has a wonderland effect.