Applying to colleges isn’t a team sport. I don’t understand what you hope to achieve by coordinating your applications so they complement each other instead of standing on their own. Are you hoping that tying your sister’s app to yours will give you a better chance to get into an ivy than you’d have on your own? Or do you think it will drag her app through into a college her stats might not otherwise be competitive for? Some of both?
I don’t think this is a hook. I’d be concerned that adcoms might look at the way you present all the shared activities and wonder about your ability to work alone. If I were your parent I’d be worried both of your apps would suffer because your app isn’t wholly you, and I’d be really worried about your reactions to the results. Are you going to resent your sister if you get rejected from colleges you think you might have been able to get in on your own? Is your sister going to feel guilty if you don’t get into your dream schools? How are you going to feel if your sister’s story is compelling and she gets accepted to an ivy and you don’t?
I’d create your application lists separately and compile your applications individually. Make sure you devote time to finding solid matches and safeties you’d be happy to attend.