They all look like roos except for the youngest white one. If you want a for sure female then get a type of sex link or a barred rock or something like that. Don't get rid of them just yet though, because they won't start crowing for a few more weeks, and you want to be sure that they are males...
back right looks like a female so far and so does the one to the left of her. The one closest to the camera looks like a male. I could be wrong though. Oh I didn't see your three new pics. Its only the darker brown one that might be a cockerel cuz of that comb, but check the neck feathers...
Well a large comb, pointed neck feathers, and dark red on the wings and chest is what I go by to help determine gender. But, are you 100% sure its an Easter Egger?
That does look very much like a buttercup. Wait a few more days for its wings to start getting feathers, and if it looks like this pic then it is diffidently a Buttercup.
baby Buttercup chicks
Adult Buttercup
This looks very much like a roo. Sorry :( He has dark red shoulders and is getting a comb, and his tail feathers are sticking up straight, and his neck feathers seem to be pointy. You probably have a cockerel. I'm hoping i'm wrong, because i wish you had a pullet, but it is most likely a...