EdgeC - what state are you in?  I, too, am in Zone 7 (sandhills, NC).
Based on your coop size, I'm thinking 25 is your max number.   I was at max during Hurricane Florence. They couldn't be free ranged or out in numerous tractors, that were either directly damaged or couldnt be moved due to debri in our yard/pasture, as changed predator level was horrendous.  The birds turned on each other in boredom & anger (? - roos not normally together).  More than one hen was pecked to her death & others were stressed more from running from coop mates than from storm itself.  Several roos killed each other - either directly fighting or thru heat stroke when quit fighting. My numbers didn't go down during the hurricane, but AFTER due to overcrowded accomodations.
Your large run is awesome for that # of birds.
Have you considered any types of tractors combined with paddock/free ranging?
Are you planning on clan mating all of your different breeds? If so, you would definitely want additional coops/runs for at least the breeding season to keep the individual breeds/lines "pure".  If able to keep coops/runs same size for that number of chickens, great! Or a smaller flock size per group would allow for smaller coops/runs...
I would LOVE to work with both the breeds you mentioned - especially as you improve meat producing qualities w/I them.  I've had both breeds as hatchery stock - they were neither good egg producers & actually poor "meaties" who took much longer than "frankenchickens" to get to any weight for table birds....  very disappointing, actually, considering they are dual purpose breeds (Australorps & Brahmas).  Which variety of Brahma do you have? You may have said & I missed it...  Have you considered Blue Australorp?
I'm a little jealous!  I'd love to be able to have that type of incubator and hatcher. Currently, we have 6 adults in my family & 2 grandsons whom are all heavy chicken eaters. The dogs (6 total) & cats (10 total) would be able to be fed more fresh chicken if we had a better hatching system.  I do know there are other breeders in NC using cabinet incubators & hatching/selling chicks.  Some are making strides in improving thier own flocks as well as the chicks/ducks that they are selling!!  I don't know any that are producing Australorps or Brahmas.
With the numbers of chicks you are talking about, you'll need/want a sheltered (climate controlled?) brooder area w/ separate brooders for different ages as well as breeds (?) of chicks. Then you'll also want coop/run or tractors to do the growouts - both ones you are keeping & others you may be selling... 
Besides "making your own" meaties, there are now other breeds of meat chickens you can raise, besides Cornish cross.
As an owner that has done some breeding/hatching (not currently), I like knowing which flock my chicks are from. Being able to purchase different & separate lines from one breeder is great!  I hate getting "purebred" chicks from someone only to have some feather in differently & finding out the parents of two flocks were free ranged or got loose together. Especially when those purebred chicks may not be the greatest & were VERY expensive for me.  If I had wanted mixed chicks, I could have purchased locally (same town, on the way home from work) rather than traveling many hours cross state, setting up brooder in hotel room since couldn't drive any longer...
In our area, there are currently a LOT of mixed chicks for sale at low prices. I don't know if these sellers are selling all thier chicks.