70%cocoa :
Is the duck you're planning on breeding from the one with the bib that goes all the way up the neck to the bill? If we are just looking at bibs I think that the other black duck is better. Her bib is patchier but it doesn't go up her neck and she has a lot less white round her head. I think that the hardest thing to get rid of, as Tbitt has said, is white on the face and up the neck. Other than that, inheritance of bibs seems to be a bit random. It's definitely the case that two birds with perfect bibs can and will produce offspring with messy bibs. If you have one bird with a messy bib then you can improve the offspring if you choose a mate with a good bib. Bibs can definitely be improved over time but I think you'll need a better bibbed drake to do it.
With the white wing feathers, it's not unusual to get uneven numbers of white ones on each side. As Oregon Blues says its much better to have even numbers but uneven numbers would not put me off using a bird for breeding. Inheritence of wing feathers seems hard to pin down. I have two black birds each with 5 white feathers on each wing. They had two offspring - a duck with two whites in each wing and a drake with none. Kinda random. I can't see if your second black duck has the white wing feathers but she may be carrying the genes to produce them.
Type wise, they could be straighter in the back and deeper in the chest. Overall you are looking for a more stocky, compact appearance. Your birds stand a little too upright - chests should be a bit closer to the ground (but still higher than the butt).
I agree with suggestions to source a better drake - unless you are not too fussed about the breed standard. I'd use him with both your black ducks. Try to keep track of the eggs so you know which mother they came from. Good records will help you work out who is producing the better offspring. With a drake, look for one with bib that is not too big (even on the small side, about the size of an orange) and as little white on the face and neck as possible. Also really avoid any drake with a bib that extends too far below the middle of the chest. Try for a bird that's less upright than the ones you have.
Get a blue or silver drake. A silver drake will give you 100% blue offspring. Blue offspring are easier to sell too - most people want blue ducklings.
Wow that was really helpful, I will use the other duck as I have enough to try to accomplish already. I could go get better stock but that would take the fun out of it for me. Though I will look for a better drake as I don't think any of the three will improve the offspring. I will post pics of the other two.
This is fun!