Snow bunny

With the chick with trouble walking, if there are no obvious health problems prevalent, I wouldn't worry about it.

One of them falls over a lot? I would check her feet for Bumblefoot: https://bantamfan4life.wordpress.com/bumblefoot/

On the aggressive behavior, it is normal for bantam rooster to be aggressive, and the mother hen is probably aggressive b/c she is protecting the chicks. Hope this helps!