Me and my friend put 3 smallmouth about 5 inches in his half acre pond last year. We really didnt think they would live just hoping. But the other day I caught one of them from it on a senko. It was about 8 inches grew quit a bit.
I dont think that smallies would reproduce in a pond unless it was deep with some rocky shoreline or humps for them to spawn on but they will live in a pond if you put them in there. I think the biggest reason for largemouth is that they will reproduce and you will always have new fish coming into to system. I dont know the temp range but for smallies but I would think even a pond that is 8 feet deep or so would be ok for them. What a great surpise that would be, nice job once again!