With the absence of beards, muffs and/or tufts you can pretty much rule out Aracaunas, Ameracaunas and Easter Eggers. With most of the chicks being either blue, black or splash in color I would say that they came from blue parent stock but breed would be in question.
Tailed Araucana. Araucana come cleanfaced and tailed also, but it is not the standard. I have a few running around that hatch out of my rumpless tufted breeding pens. Some people use tailed birds as breeders to keep their offspring from getting too short of backs. It is not uncommon to see Araucana with tails, just since they are not per the standard everyone thinks they don't exist.
Looks like you have a few nice rumpless ones also. Do you have any with tufts? You can breed the rumpless to the tailed ones and then cull for tails. Eventually you will get down to only a tail popping up everyonce in a while.
Decided to keep these a few more weeks to see what they turn out like. There are some of the Tailed ones that do have a tuffs. One even has double tuffs.