It seems to me that asking about the state of something in "your" Everett branch while it's outside your light cone is rather meaningless. The question doesn't really make sense. Someone with a detailed knowledge of physics in this situation can predict what an observer anywhere will observe.
So, if it was someone you care about instead of a cat, would you prefer that this happened or that they disappeared entirely?
It is still not meaningful from a physical standpoint. If you were to throw something I valued outside my future lightcone, then I would take the same as you destroying said thing.
And may I remind you that Schrödingers cat was proposed as a thought experimental counter argument to the copenhagen inteprentation, so asking if it is alive or dead before I have had particle interaction with it is equally meaningless, because it has yet to decohere.
Here's the new thread for posting quotes, with the usual rules: