Dwight -- this "string" brought up several thoughts in my mind.
First, very nice job on the structure!! I like the long, linear shape on your trees. That will be great for fishing. That 3-d sructures are great as well -- nice to have some height!
I was also very pleased to read your description of the water movement and dissolved oxygen. Just giving advice or opinions long distance is often a dangerous business. It's obvious now that you're in a good area of ground water flow, and that should really keep your water quality problems to a minimum. You'll actually have a little less fertility than "hill ponds," but that's often a GOOD thing in the north country.
I'm not sure that you really are missing any fish species. Norm may chime in, and he'll gently disagree, as he really likes diversity!
However, if you want a pond sustained by natural reproduction of your fishes, then you've got a good complement of species. Do you have any common carp or buffalofish that came in from the stream connection? As long as you keep up the largemouth bass density, which should happen naturally given your description of your pond, then the bullheads won't be a problem. The bass will crop off most of the small ones, and all you should see is a few big ones. I would keep cropping the northern pike, as they just can do too much damage as they grow. They can really take some big fish as prey items. While I like northerns in general, and like to fish for them, I think it would be best to keep their numbers very low in your pond.
As for plants, I'm firmly convinced that the submergent plants are the key to good ponds in the north country. That's where the small panfish and small bass can hide and feed. I honestly don't think that the emergents add very much value. You could establish cattails in your shallow area, and as I assume your pond is relatively steep-sided, they probably would not cause big problems. However, I'd rather see the submergent plants growing in your shallow area, and just skip the cattails. Let's see if anyone else comments on that thought.
