Wow! What a great place. In my mind the size of this pond is going to make it tremendous fun but also a lot of work if you really want to manage it well. I'm also from MN and I've seemed to have solved the overwinter issues in my pond but it is only 1/2 acre. I actually think the larger pond will be easier in this respect since the chances of supercooling are zero. Based upon what I've learned and read I think I'd install one aerator. I'd do it like someone suggested above, use an electric pump by the house with air lines into the pond. You can build this whole unit yourself for $500. I honestly don't know for this size pond if you need to circulate water from top to bottom. I know that the DNR aerates ponds this size in MN with a surface unit that just keeps an area open and allows for some natural air exchange. The experts on this forum will have to give you advice. I think the biggest amount of work for this sized pond is going to be predator control, especially in your area where otters are present. Then again, perhaps a few otters won't make much difference in that sized pond. The least expensive and easiest route to take would be minimal aeration and then just stock the pond with the right mix and let her go. You'll have to get help on the right mix from the experts. I think a guy like Dave Willis from SD would be a good source of info for northern lakes. It seems that every pond is an experiment and yours will be too. That's why their fun.

Gotta get back to fishin!