Which red one? The one that is all red/brown with yellow legs is a Rhode Island Red. I did not see any Sebrights.
I think the white one may be an Easter Egger, too.
I think the one that you are calling a plymouth rock is an Easter Egger Bantam.
Cackle has more bantams then anyone I think. You have a nice mix there. Post again when they are all about 8 weeks and we can help you with genders (silkies will take longer). 😊