Well they are still young according to their how developed the feathers are... meaning I don't see any long flowing
obvious saddles YET and the head crest is still pretty short... streamers can be so subjective.
The one with lighter pajama pants is going to be a Blue, not black.
The one with color leakage int he hackles... I would still be on the look out for male behavior... but if you aren't seeing ANY, try not to worry too much. Males will try hard to mate the laying hens.
Some Silkie lines are known to lay much later than many other breeds. And they SHOULD be smaller than your other standard breed chickens as they are considered a bantam though some are larger than accepted by the standard of perfection.
Many people still call April and May spring. The later they hatch, the later they seem to lay... not only due to age but also birds coming into lay during fall tend to do so a bit later. AND I have had Silkies crow as young as 4 weeks old. I could probably give a more definitive answer were I able to watch in person... since Silkie lines and feature vary so greatly but activity is huge indicator. Most black birds can get that green sheen so that is not a good indicator.
Hoping they're ladies for ya!