Sounds like if your pond is spring fed and stays cool, then there is a decent chance of trout survival. If the DO levels can remain high enough, you might have a chance. You may be able to only hold brown trout over, but you won't know until you stock trout. I would consider stocking 20-30 of each species, brown, brook and rainbows and see how they do. Then depending on the results you can consider one species over another. Tiger trout and the favorite palomino(golden rainbow) trout are also options to consider. Once your predator base gets established you will need to stock trout at least 8" and closer to 10" to make sure they don't become expensive fish food. Trout will need to be restocked periodically as they will not reproduce in your pond.
HSB should do well in your pond with the cooler temps, particularly the larger fish as they need cooler higher DO levels. I see no reason why you cannot stock them. They will need to be restocked periodically though as they will not reproduce. The same holds true for the walleye. They are more of a cool water species as well and it would be very remote they would reproduce, so there would be a need to restock them. For the HSB and WE, restocking can be done annually or every other year to allow you to have well represented size ranges available in your pond.
If you pond is staying chilly enough for trout and is in NW PA, RES(redear sunfish) will not be an option. They are a great species for the south, but when you start getting north of the Mason-Dixon line things get blurry and throw in the heavy spring influence of you pond, they just aren't going to do well.
As TJ said, consider YP of crappie. Crappies are a challenge to work with at best while YP are far more easier to manage. Crappies are fine eating, but I think YP are even better. Plus YP make a far better forage base, particularly for WE. Since you will not be feeding, you are going to need a very solid natural food chain.
Go with the SMB over the LMB in my opinion. It's going to be easier to maintain a self sustaining food chain with SMB where as with LMB, they will eat everything and themselves and cause a real challenge. It will also be difficult on your WE as the LMB out compete them and will eat even the larger end stocker fish.
Species I would consider for stocking into your pond:
Trout(any of the 5 varieties I mentioned)
walleye(WE)
hybrid striped bass(HBS)
smallmouth bass(SMB)
yellow perch(YP)
pumpkinseed sunfish(PS)
golden shiners(GSH)
fathead minnows(FHM)
banded killifish(BKF)
This fall if your pond level is correct I would stock your forage fish. I would stock 5 pounds of GSH, 5 pounds of FHM and 500 BKF. Zett's is the only place I know that sells banded killfish and they are in northern WV. They call them bull minnows. It may be a pain to get them, but if you are going on a straight natural food chain with little to no feeding, I strongly recommend you get them.
I would then give your forage a full year to reproduce. The following fall I would stock the SMB(75) and WE(15-20). The following spring, I would stock the YP(250) and HSB(20).
When you see your SMB have reached the 12" range, then I would stock the PS(300). This will make sure your bass are big enough to control the PS so they do not over populate and stunt.
Trout can be stocked the same time as the first SMB and WE, but I would hold off on stocking them at least one more year.
The recommended stocking numbers are on the lower end as you will not be feeding and since you want to hold trout you cannot fertilize as this will run the risk of lowering DO levels. This stocking recommendation will IMO give you the best chance at producing fish of all species in quality size fish relying solely on a natural food chain which is a real challenge in a smaller pond. Do a search on spawning habits of the FHM and GSH, you want to make sure they are making lots of babies in the first year. BKF spawn very similar to GSH.
If you want to add crayfish, I would recommend finding the closest pond or lake to your place and trapping them from there. Then transfer them to your pond. Just a few dozen without predation should take hold. That way you are getting a species adapted to non flowing waters that is already found in your area. Fish farms most often sell species that are not native to the Northeast and you don't want them...
