Thanks for the many constructive comments. Especially from Mr Pondmeister himself!
I guess the road to Hell is paved with good intentions. I originally planned to transfer the CNBG into the main BOW and replace them with fingerling trout, which I would feed & fatten up, then release in February to fatten spawning LMB. But the trout arrived a couple of weeks late and had already grown to the point where they were good eating size for bass, so I had them put directly in main pond. We've not had a winter since the pond filled where CNBG couldn't survive in the forage place, so I thought it was pretty safe to keep them there. A bad assumption, as Bob Lusk points out.
Given that I'm in a damned if I do, damned if I don't situation, I think I'll leave things be. Maybe ice will form quickly enough on the forage pond to buffer the worst temp extremes. Unlikely, but I can always hope. It takes a while to refill the forage pond naturally, usually at least six months, so if things don't work out it is probably best to just let them die & get eaten by coons, turtles, water birds, etc. The water will still be there for stocking when it warms.
I've read several articles about sunspot cycles that predicted the 2020s/2030s would be colder. Maybe I should have paid more attention & stocked accordingly. Even in my main BOW, Florida LMB might not make it. Hopefully the F1s and NLMB will be okay.
IMO, You're over thinking this. Fish live under ice just fine. Stressing them during that period is as hard on you, as it is on the fish ; )
