Welcome from Middle Georgia! So glad you have joined us.
Barred Rocks do well raised in confinement and would be little tilling "machines" in the garden. But make sure they cannot access it during growing season or you will not reap the rewards you plan.
You are in a colder part of the state than me, and IMO if you are starting with baby chicks, wait to get them in March, so the weather will be warm enough to move them out of the brooder to the coop when they are 5-6 weeks old. Even in Macon area March born chicks couldn't be moved out until full spring was here. "They" are predicting a cold, maybe record snow winter for our state this winter.
I have no experience with ducks, but from past info on this site, would make sure you get a female duck if they will be living with the chickens. A male duck among hens is not a good thing. And careful with water/pools around the chickens. You may want to consider a small separate area for the ducks.
Also be careful about trusting any dog unsupervised around your flock, there are so many reports of a friendly dog killing the flock - happened to a friend of mine after several years without an incident and was a devastating surprise.
IMO allow more room in the run than the minimum - I had to expand mine when my small flock were grown - with the minimum areas quoted, they were just too crowded for comfort. Mark off a mock up area of what you think will work and picture 5 gallon buckets to represent each full grown hen as well as water founts, feeders, flock blocks or other "entertainment" items you may want and see how full that area gets. It is much more difficult to build/expand their home after they move in.
Good luck with the new adventure, raising and tending your own flock will be so much fun for your family and yourself.