Do you have a pellet feeder for your trout?
One option is to fatten up the trout that learn to readily take pellets. I am not a "trout guy", but there are a couple of people on the forum that do that in their "trout only" ponds. The kids can then catch the trout at the size you select. They should be able to catch most of them from the pond. You can then re-stock trout at that point, or you could have "ladder stocked" a few trout every year. (That typically costs more unless you can buy trout in small batches. You also have the chance of catching smaller trout and causing a hook mortality, or making them hook shy.)
Another good option (as the wise locals posting above have suggested) is to add a type of panfish. That is what I usually target with young, new anglers. Do NOT add normal BG. They would quickly take over your pond, since even the largest trout would not make a dent in their numbers. I have read some of the pumpkinseed threads from our members in the NE U.S., and they sound like an excellent candidate.
If you can't find any to purchase, perhaps you can bucket stock a few to get started. I am sure 3 and 6 y.o. kids would be perfect for helping you perform that project if you had some decent fishing areas for PS. Do you have any local fishing buddies you can ask?
Another option is to add another species of fish that will not reproduce in your pond. Hybrid striped bass might be a good option? With enough forage, they will get large quickly. Walleye will not grow as quickly, but are very tasty if your family eats their catch. (I love trout, yet I think walleye is even better!)
Another way to introduce fish that will not reproduce is to have a single-sex pond. If you could catch yellow perch, or smallmouth bass during the spawn, and CORRECTLY sex them, then that is another option. (That may be an expert-only option?)
Finally, I like that you bit the bullet on the black crappie "mistake". Is it relatively easy for you to drain your pond to start over and then have it quickly fill over the course of a single spring? If so, that is a huge advantage for you! IMO, you can then experiment on whatever good advice you get. If the pond gets messed up, once you have fished out your expensive trout, just drain it and cull 100% of the fish and start over.
No matter how you go, I would like to see another forage species. FHM are tasty, but slow. Therefore, they are great to start a pond, but they can be completely eliminated by the predator fish in some ponds. I don't know how close you are to Smith Creek Fish Farm, but they do normally carry Golden Shiners. (Even if you are not close, that suggests they are a viable forage species for W. NY.)
I also see that Fish Haven Farms (east of the Finger Lakes) does carry hybrid BG, which suggests they are probably viable for your latitude.
Good luck on further enhancing your fishery. I love watching projects designed to put more fish on the lines of young anglers!
