Those are adorable and look very well-made! And I like all the explanation you put with the stuff you've made. I have no input/advice to contribute, but good luck learning to make teeny tiny clothes, it looks like you're doing really well so far!
I think it's adorable and I love the fabrics! The two prints look nice together, especially since it's for babies/toddlers. I prefer it without the sash, but I think you could put a little elastic in for shaping at the waist area if you wanted, but I think it's good on it's own because it's roomy so the little one can move around. Very, very cute, good work and good luck at your craft show!