Ah, yeah, getting chicks from a mixed-color pen isn't going to help you much with breeding for color, unfortunately. Even if they end up looking fine on the outside, they could be carrying genes that make them throw off-colored chicks. :hmm I do hope you're able to get what you're looking for...
These are WAAAAY too young to make a good call on who to keep for type. They may look okay now, but grow up and have the wrong type. Some of mine are a good example of that, looking perfectly fluffy and poofy as juveniles and maturing into scrawny, skinny, upright birds with poor crest...