Sounds like you have a fun
project coming together! I am also located in MI and thinking of stocking the several acre farm pond on our property so I have thought quite a bit about the overall design for a northern setting. My
experience is in freshwater
aquaculture with Nile tilapia in a recirculating aquaponics system in a much warmer southern location.
First off, most of the fish your local hatchery suggested are carnivorous, or another way to think of them is that they
feed high on the food chain. This is not surprising since most people's preferences go toward the better tasting carnivorous fish. Rock Bass, Large Mouth Bass, and Perch are all high feeders. Sunfish is an herbivore/omnivore and you could also throw bluegill in there too. Catfish is a bottom feeder that feeds on benthic organisms and deadfall from above. What you will probably want to do to achieve a balanced system in your pond is to simulate a natural ecosystem with each trophic level providing some benefit for yourself, i.e. edible.
So the basic layout would be three to four different species, each chosen for their what benefit they give the whole system and what level they feed on. You will want a filter feeder, herbivore, predator, and detritavore. This will provide a basic functioning ecosystem. Now which fish you chose for each of those rolls is up to personal preference for what tastes good to you, what is available, how hardy it is (does it get sick easily and tolerate the
water conditions in your pond?), how fast does it grow, etc. The classic Chinese carp
polyculture works in exactly this way and they have been successfully raising lots and lots of food for centuries in this fashion. They use the Black, Grass, Silver, and Big Head carp together to produce incredible amounts of edible biomass per acre. Beginning research can start here
http://en.wikipedia.org/wiki/Aquaculture_in_China
I would also suggest adding an abundant amount of nutrients into a system like this once it is established since our cold northern inland ponds are a little low on primary production. For my pond it is already provided by the runoff from a neighbors farm unfortunately. If you don't have anything charging your pond with fertilizer then adding ducks on the pond or some kind of farm animal on the slopes near the pond can
boost productivity quite a bit. Basically you want the pond to go eutrophic so that there is lots of primary production (plankton and algae). Your filter feeders will consume the algae and plankton stimulated by this fertilization, your herbivores will eat the grasses and plants stimulated by the nutrient rich water, the carnivore will feast on the young offspring of the others to keep their populations in check (overpopulation leads to food scarcity and smaller fish all around), and the detritavore will clean up the bottom and feast on the waste of the others. Ducks provide the input and help keep duckweed and shore plants down.
A note on tilapia: they can become incredibly invasive if they get out into natural waterways (carp too for that matter). If you go this rout be sure you have protective measures in place to prevent the accidental escape of your fish.
I hope some of this helped. I know I didn't give any specifics on species but every situation is different and the overall design and balance is what you are striving for. Personally I am leaning toward seasonal Nile tilapia, crappie, green or pumpkinseed sunfish, and catfish/bullhead (not sure how they taste in a farmed pond) with muskovy ducks and wild geese (already have plenty of these). Let me know if you have any other questions and I will be happy to help!