Regarding dairy, the first 2 weeks of the meal the only dairy used is butter, and yes Ghee would be a perfect substitute, or any other cooking oil honestly. You wouldn’t need to sub anything else as there is no other dairy those first 2 weeks of the meal plan.
For weeks 3 and beyond, we occasionally utilize some dairy in the form of half and half or heavy whipping cream or cheese, but all of it is in very small amounts (we’re talking like 2 tbsp or 1/4 cup here and there) and for the liquid dairy, these would all easily be replaceable by things like coconut milk or coconut cream (which is what the recipes she had in the first 2 weeks do!) and then for the dishes with a little cheese, there is only 1 recipe where the cheese is a main component- the eggplant lasagna- the rest of the dishes it’s really just a garnish type thing in small amount so you could simply sub a handful of nuts or seeds in place of it or some nutritional yeast (which we utilize in other dishes because it has a cheesy flavor!)