Ed, I'm not too interested in variety, variety, variety. It has been many years since I've had more than 2 breeds and usually, only one.
For me, a flock of a single type looks good
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There can be problems in any flock but there's the saying that "birds of a feather . . ." You know how it goes.
My Australorps hang out together and the Barred Rocks hang out together, or they pick on the Aussies. They are a fair amount larger. I've had roosters of various breeds but that was just for fun, I wasn't interested in hatching eggs.
The only other one from your list that I've had are the Buffs. And, I had them with Ameraucana. That combo looked rather odd to me but the quiet Buffs and small Ameraucana got along just fine. Still, they didn't convince me to continue much mixing and matching.
What I think would be lots of fun would be to have Plymouth Rocks in all their varied colors. Gritsar has a flock like that with her Brahmas. I just wish Australorps came in greater color choices. Once again, I wouldn't care about fertile eggs but the hens only varying by color has appeal
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Steve