Hum? I guess my text got deleted somehow. Was wondering if you had seen my last comment?. And what you ended up using.?
https://www.backyardchickens.com/threads/coop-door-lock-suggestions.1572764/post-27091214
Use these gate latches. They can be opened from either side. Lockable from either side as well. If the door sags there is a little bit of allowance. If it moves way out of alignment then the bolt can be moved up or down. So unless someone actually locks you in, then you are safe.
For your...