Thanks all for your tips. Still working on Napoleon's bell ringing. I don't take him out every time he rings it now. He's ringing it less as a result. Whenever he rings it and I kind of know inside that he just wants to play, I say to him: "Not yet." Just to let him know I heard it but not prepared to take him out yet. All the other times when I know he has to go, I stand with him at the door and won't open it until he rings the bell. Hopefully, in time he will learn that if he really has to go, he will ring the heck out of it and won't stop even when I say "Not yet"
We haven't had any accidents yet for several days now. I should be happy he's not afraid of the bells anymore