Howdy, jimmyt.
FOrgive my stupidity, but I have always wanted to own a pond to fish in
If that's stupidity, I doubt anybody here wants to be smart!
Large CC can take up a lot of a pond's available biomass; you are correct to suspect that this fact may have had something to do with the previous fish kill.
Removing some/many/all of the Channel Cats (The last option may be a Sisyphian task, especially if the CC have managed to reproduce and recruit in the pond. Ya seen any
little CC?) should not have a overwhelming influence on the balance of the pond. While CC this big are undoubtedly having an impact as predators of BG and Crappie, the LMB population (after a year or two of spawning; those CC won't be coming out instantly) should be capable of taking over any predation affected by a reduction in CC.
We have had a few threads concerning the catch and removal of large CC (a subject not far from my own heart), and if you are interested in some other baits/techniques to try they are good places to look for ideas. Catmandoo my be our champion great big CC remover.