Are the LMB keeping down the crappie population by eating the large ones, or are the tiny BG keeping down the crappie population by eating thousands of fry?

Even if only a few crappie reach the correct size to spawn, a female BCP can still produce 40,000 eggs.

If Pat has a relatively small number of trophy size bass, what is eating the 2-3" BG in the pond?

Pat, have you checked for stunting of your BG? I agree with jpsdad above where he suggests adding a few smaller bass each year. I believe that would extend the balance of your awesome pond a little while longer.