Undigested cellulose is just insoluble nasty fiber. I get the irritation. But why would inert fiber mess with serotonin or be goitrogenic? And why, halfway through your list, did you randomly change gears and mention chemical substances (almost everything is a chemical substance) and polyunsaturated fat? It makes no sense yet. Please explain.
Undigested cellulose, leads to increased inflammation, irritated digestive track, increased serotonin levels, thyroid suppressing goitrogens, chemical substances, polyunsaturated fats, etc etc
Steak, eggs, potatoes - fruits, nuts, berries and forage. Coconut milk and potent herbs and spices. Tea instead of coffee now and teeny amounts of kelp daily. Let's see how this does! Not really had dairy much, and gut seems better for it.