I'm wondering what the source of these birds is as some are looking like mixed breeds. I am also going with an EE and Welsummer for the first and second. The rose combed black bird (trhird photo) appears to have dark shanks, possibly feathered even, so definitely not a Wyandotte....which makes me think mixed breed and that leads me to wonder about the source of them. The last two could be black sex links, but it's unusual for them to have such a red breast as the last one does.
I agree that they are all looking like pullets so far.