I'd be hesitant to use size/build/leg thickness to determine sex, especially since we're not entirely sure what the breed is--different breeds have different builds.
As for breeds--they're all hybrids of some sort, and I wouldn't feel confident saying which sort. The first could probably be lumped in with "easter eggers" with those green legs and that plumage.
I'm inclined to think that 2/3 might be red sex-linked hybrids, in which case you're in luck--those particular colors would indicate you have pullets. Calico princesses (#2?) are a type of red sex-links, 3 could be any mix of things, but looks a lot like the red sex-links you get from Rhode Island Reds x Delaware hybrids (or another variation with the Columbian coloring->black tail)
Hatcheries like sex-linked hybrids because it's easy to sort pullets from cockerels. That's no guarantee that that is what you have (3 in particular could also be an easter egger, in which case it could be a cockerel), but it's a good shot.
There are two main variations of sex-linked hybrids: black sex-links (a barred hen x non-barred rooster)--pullets are (mostly) solid colored black and cockerels are barred; and red sex-links (a silver hen x gold/mahogany rooster)--female chicks are darker at hatch than males, and grow up to various shades of red, while males are a creamy lemony color.