I have a Gold Star who is the leader of the hens and started laying way before the rest, Silver Laced Wyandotte who is laying when she wants already. Then for the sisters we have Easter Eggers, Buff Orpingtons, Black Australops, and Barred Rocks. Of those pairs the kids already picked out their EE when she was a chick, there was enough distinction between the two. Today one of the BR was pecking me while I was cleaning and trying to get their curtains in, so she is going. The other two sets of sisters will be a toss up. I am not super new BYC but I can never get to the place of starting a NEW thread.
I personally would keep the Black Australorps and Buff Orpingtons as they are very hardy breeds with a very calm and gentle temperament and are good layers to boot (especially the Black Australorps), and I would keep the Gold Star, which is one of many labels under which some hatcheries market their Red Sex Links. But no matter what label they are marketed under, Red Sex Links are egg laying machines, so I would keep the Gold Star for its laying ability. Of course it's strictly your decision which you keep, and you should keep the birds that you like the best.