Arum is actually talking about this. Who would you have? It is a weird thought. While Williams could certainly fight at middleweight, you'd think he'd at least detour at 154 and then want a fight at 160 before he'd take a fight with Kelly. A jump right to this fight at 160 would be ballsy as hell.
I'd have Kelly stopping him just due to the Punisher not being used to the weight. Maybe it would be different if Paul went up more gradually though.
Kelly, due to the main focus fighters already having signed their own fights, doesn't have much of a lineup to choose from. Beating Williams to a pulp would do little for him. This fight should definitely NOT happen. Winky seems most logical given the lineup he has to pick from.