Yes, needs Alnutrin for meat and bone, especially since you plan to cook the meat. This thread covers how to use Altrunin with cooked meat Alnutrin cooked recipe questions.
You also need a good quality source of omega 3 with some kind of fish oil, though avoid liver-derived oil. Human omega capsules from a decent brand, or pet omega from a respected brand like Nordic Naturals will suit. Recommended dosage for cats is around 30mg EPA+DHA per kilogram of weight per day. This can be given 1-2 times a week in a larger dose instead of daily. Needs to be added straight to the food before a meal as it degrades quickly. Shouldn’t be frozen in a batch, either.
You want to introduce new proteins one at a time, like you would with a new cat food. Personally, I wouldn’t mix them and keep them separate in some capacity even once your cats are used to all the proteins involved as many cats enjoy the variety in their diet.
I don't know what's in those blends or which Alnutrin you plan to use but cat food needs liver as well as a calcium source... But not too much of either. Apparently Alnutrin is very helpful in answering questions. I use an Alnutrin supplement that has egg shell calcium so I don't overload the cats with bone since one tends toward constipation.
As for cooking, I add the Alnutrin supplement to the meat after cooking.
EZ Complete is an excellent supplement. We used to feed it but one of our cats developed an intolerance for something in it; I'm pretty certain it's the green-lipped mussels.