Welcome to BYC! Those breeds are all quite calm and docile, although the Barred Rocks are not quite as gentle as your other standard breeds and might batter your Japanese bantams, and I think you are wise in not putting Silkies in with them. Also, unlike your other breeds, Japanese bantams are not very cold hardy and you get some very cold, winter weather in Pennsylvania. Whatever breeds you decide to get, good luck with your flock.
X2
That was the one I was shy of.
Getting the right breeds up front eliminates a host of problems.
I've had barred, white and partridge rocks, australorps and brahmas.
The only drawback with the brahmas is their tendency to go broody so you'll need a wire bottom cage you can elevate to break them since you won't have fertile eggs.