If you truly want dual purpose I don't know that many bantams would fit your bill (I don't know of any that folks use for meat as well as eggs, so I don't know if you could find a truly dual-purpose bantam). My Cuckoo Marans fit all of your criteria. I would say the weakest area out of those you listed would be laying ability. Mine lay very well when they are laying, but they like to take long breaks and they do go broody--if you want a bird that goes broody, you're going to have to sacrifice some production quality.
But, they do lay fairly well, they do go broody (mine are excellent broody hens and excellent mothers), they produce nice heavy cockerals that apparently folks find tasty (I wouldn't know, I'm a vegetarian.
Though I do pass along my extras to other folks' freezer camps), and they are calm but active and free-range well (they have chicken common sense
). If you want to breed them I would suggest finding breeder stock, not hatchery stock. You'll likely get poor quality birds and poor quality egg color from hatchery birds, as they often have other breeds crossbred into them at some point and the hatcheries aren't selecting for type/quality when they breed.
My Ameraucanas also fit those criteria, but they are a smaller bird and so I don't know how dual-purpose they really are. Again I would caution against hatchery stock--in the case of Ameraucanas, you won't get true Ameraucanas at all from a hatchery (In case you didn't already know--sorry if I'm just repeating stuff you already know.
). You will definitely get mixed breed birds.
