I love it and lucky for you to adopt/adapt a coop.
This though " (tip, knock them into cold water and they’ll freeze)" referencing Japenese beetles. I heard somewhere else someone say they knock them all into cold water, freeze it, and then let the chickens have it. Is that what you mean or literally, the cold water freezes them? We have a lot of them here on some of our birch and raspberry bushes mostly.