Reg, I want to say many things in this, but will keep it as short as possible.
First off, great choice on your chicken ark/tractor/coop, I based my design off of this very model, with some differences to meet my needs. The key there is to meet MY needs. You do whatever you want. They're your chickens. Everyone has their opinions, and while this site has worked it's way into what I like to call "best practices", you can do what works best for you. May you have problems with pecking order issues? Sure, but you may not. Learn as you go along with everyone else here.
As for your chicken choices, go with whatever you want. I'm going 4 chickens of four different breeds for their colors. They look pretty. Again, do whatever you want.
I'm sorry that you got so many strongly worded opinions here. My experience is folks are very nice here. I think you just got some strong opinions.
Good luck and enjoy the experience!