The "two pond option" was kind of part B of my fish contamination question.

If I did manage to establish a viable YP-WE-SMB fishery, and some BG or LMB made it into that pond, would a few invaders eventually take over?

For my conditions and climate, I think BG would easily be the most successful forage fish and LMB would be the most successful top predator. Once they entered, would a few large adult BG or LMB be able to establish a breeding population against the existing "inferior" fish that already occupy that niche? In the alternative, could a breach of several thousand fry establish a breeding population, or would they experience close to 100% mortality due to predation?