P420 and P430 mean bad cats, not all that other stuff. If those are Chicom cats, they do not last, usually not even a year. But since you put new cats on and fired the parts cannon, the only other thing to replace is the ECM.
When you get cat codes, it's most always the cats. It could be the wiring or the ECM, that's it.
When my cats and chicom cat failed, I purchased a Magnaflow cats and y-pipe and all has been well going on four years now.