Both birds look like pullets, at least judging by these photos. However, Silkies/Silkie mixes are notoriously hard to sex until they crow or lay. Close-up photos of each bird might help us be more sure of their gender.
Close up, individual pictures would help a lot. To me, they all look like cockerels with the way they are standing, but that could just be weird timing on the picture. It would also help to be able to see their faces. I have a couple of smooth black Sizzles and frizzled Silkie pullets that are a little older than yours, and their crests are much more round and their combs are nonexistent, though I can't see the combs or wattles on your birds(I'm saying yours looks pretty boyish compared to mine ).
The Cochin and blue seem to fight/play a lot, and I'm seeing a lot of feathers in the coop - a little concerned for the blue, but I guess it would be strange for them to fight if it's a male and female, or am I mistaken?thanks for everyone's help!