The FDA actually does not know what is causing the issue yet. This is taken right from your link:
13. Does the FDA know what it is about these foods that may be connected to canine DCM?
At this time, it is not clear what it is about these diets that may be connected to DCM in dogs. There are multiple possible causes of DCM. Taurine deficiency is well-documented as a potential cause of DCM, but it is not the only cause of DCM. Nutritional makeup of the main ingredients or how dogs process them, main ingredient sourcing, processing, amount used, or other factors could be involved.
There could be a lot of factors involved, not just the ingredients you are listing. You have a lot of 4Health on you list of Ok formulas to feed. Really? What makes you think they can formulate any of their recipes correctly if they cannot get the grain free line safe? Diamond does not even employ one board-certified veterinarian nutritionist as large as they are. Nor, do they do feeding trials.
The FDA states over and over again to consult with your veterinarian or a veterinarian nutritionist. Most are recommending finding a company that is in compliance with WSAVA guidelines. Most of the foods you list do not even come close to meeting them.
