They would do the same as the red bull structure.
Newey as Chief Technical Officer who would design the overall concept of the car and any key parts he thinks need special attention like the suspension etc.
Cardile continuing as technical director building the car to this concept and lending his expertise in his key skill areas.
I think as long as Cardile is happy with a bit of power going away then things should be ok. He's a capable technical guy who's built a really decent car this year with class of the field tyre wear and predictable handling. So there's no reason for him to be demoted for anything.
Newey can also lend his expertise in design processes and software in order to give Ferrari the insane correlation that red bull have (though Ferrari correlation seems fine at the moment).
With the best driver in the world and a fast young man it would be the ultimate team. Drivers would crap themselves as they see the newey-Cardile built rocketship barrelling towards them being driven by the GOAT