Diamond is one of the most beautiful looking chicks I've ever seen and from reading your accounts of him, he has a wonderful and gentle personality I hope with all my heart you get to keep him

From my experience, authorities only get to find out if someone reports on you having a Rooster, I'm just wondering if possible, if would be worth having a word with your neighbours and those closest who are most likely to hear him, see how they'd feel about the situation, you never know you might have neighbours who don't mind?
I don't have any experience in the subject of feather picking but I came across a very interesting article which suggested chicken feeding toys - For example, I've seen some chicken toy balls which we are planning to get for our girls just as a fun factor for them. The food (treats are recommended) is put inside the ball which has holes in it for the chickens to be able to peck the food out but obviously being a ball it rolls around so they'd have to work at getting the treats out, has many good reviews - just a thought. Also I hope you don't mind but I found this article very informative too so thought you might want to give it a read.
https://the-chicken-chick.com/chicken-feather-loss-cannibalism-causes/