Hello Liz, if we made wrong size, we will give options to customers directly (making another new for free or other options), but won't ask customer to returns it.
For the colors, yes, it is like the product photo shown, but since we use a white spot light when taking photos, so the actual costume may a bit darker than the photo, the effect is just like you put it outdoor under sunshine.
Most parts of the costumes are made of polyester, but the costume accessories (like buttons, straps, sock), they will not made by polyester, I guess you can understand our meaning by referring to the photo. n_n