Is it a good idea to stock Florida bass in a pond in southern Illinois? Winters here do get pretty cold and the summers do get real hot and humid. Would Florida bass thrive here?

Not a good idea to stock FLMB in your location. F-1s might be ok but best bet for good performance is NLMB.

Rule of thumb I was told is that if your BOW ices over in winter, even if only for a few days, Fla LMB won't do well.

There are studies about this and Fla LMB do not survive in ice water conditions. But more importantly even in non icy conditions if the water is cold (north of about North Tenn line I-40 +-) they do not reach their true potential even when they survive.