My breeder (who is also a trainer but unfortunately lives in another state) has suggested that I keep him on his prong and leash in the house and correct him if he attempts to go after one of the other animals.
It is very cruel to the dog. Any corrections in this case are terribly wrong, your dog would never understand the meaning of his punishment ( prong is a correction tool used only for things your dog knows really well, but doesn't want to be perfect for some reason) Don't try anything which may suppress his spirit at this age.
By keeping him away from your cats wouldn't do any good, keeping him away from all other cats wouldn't do any good. His prey drive becomes visible to you only if he runs after the cats, but here's something powerful interferes. He is sharing one home with cats, but he cannot see what's the use of them in your pack - your cats resemble for him an injured by parent-predator smaller amimal in order to teach him hunting. You, probably, know, how wolves and foxes teach their young. Your "No!", "Shut up!" or "Leave it!" sound as some sort of encouraging signals from his mother.
1. Teach him that the cats are the members of the pack. Put him on leash tether in your kitchen and call your cats. Start feeding them some treats ( normally, a fresh raw rabbit would do well, both carnivours love rodents). Do it as often, as you can, one day you will see that your dog is sitting perfectly, doesn't pay attention to the cats at all.
2. Try to explain to him two things "right prey" and "wrong prey". Play some soft ball inside keeping him on leash in the same time and also have cats around. Don't say anything to him, if he pulls to your cat, ignore the cat and pull him away trying to engage him with the ball. Ignore cats yourself in his presence including strangers in the streets, don't react on his barks just keep on walking and concentrating on "Heel". By demonstrating him your own disinterest you train him to ignore cats. Provide him with the "valuable" prey, concentrate on the ball game and other outdoor games like tracking - another good hunting game.