It's understandable why comfrey has a love-dislike relationship among permies. It's thought of as an invasive plant (or weed to some folks). But that depends on what you use it for. We mainly use it to feed geese and to improve our chicken's egg production. So to us, comfrey is very valuable. And I can see it's equally valuable to so many other permies here too, yay!
With regards to its tending, I think you've got enough advice and I concur with them, especially regarding watering and the shade. I'd also like to add that comfrey don't like cold temperatures therefore be ready with the mulching and heat beds. And since you have pigs, make sure they don't have access to the comfrey because of their rooting habits. But I guess you already know that.
Finally I'd like to reiterate that comfreys are highly nutritious to your livestock, which is attributed to its very deep roots that can pick up on minerals like potassium and nitrogen. So don't be put off by the contradicting info.
