With fish in the pond as large as 5 lb plus pike, I'm not sure how successful supplimental stocking would be especially if you do not have any weed beds established yet. Weed beds will act to provide some cover for newly stocked fish; unless your wallet is deep. Norm Kopecky commonly stocks adult fish into an existing fishery, maybe he will respond with some hints. Without weed beds the small fish and even some slender medium sized fish are "sitting ducks" for larger predators such as big bass and large pike. The amount of structure/cover that was on your above photos will not be enough to protect small fish. The cover that you put in this winter will serve as fish attractors and places for anglers to fish.
As I see it, your current best plan is to try an manage the fishery based on natural reproduction. Maybe others can provide some suggestions. Supplimental stockings of adult bluegills may help enhance the forage fish base. If gizzard shad occur in the adjacent stream you also probably have them plus numerous other minnows and shiners. Those that can reproduce in the pond will continue and self perpetuate. Those that don't reproduce will soon be eliminated. I am suprised that MDNR will not allow private waters to be rotenoned even with a DNR permit. Are you sure that rotenone is not a possibility or is it that you just cannot buy it as a nonlicensed applicator. I am glad I do not live in MN.
