Moore has said repeatedly that he creates a system that bets fits his players. He's said that every player has a super power and it's the coaches job to figure out how to use that super power.
I'd be really surprised if Moore hired a DC that doesn't share that philosophy and approach on the defensive side of the ball. I think Staley's going to run whatever defense best fits the current roster. That might be a 3-4, but it might not be.