Master Glass:
Regarding the bell idea - if people can't hear a yell, a bell will be even less likely. A gong maybe. You've also said in previous posts that people in one room can't hear people in another, no matter how loud the yell, even through a single door.
You and I may have different ideas of what an appropriate bell would be. Ever watch a western when the farm hands were called to eat? Those things are quite loud.
And shouting from one room to another usually involves 2 doors. A bell will awaken someone, per Xanathar's. That's not through a door or wall, however. Per me, it will awaken anyone with a PP of 15 or higher (Xanathar's uses this number for normal speech to prevent sleep (without the door in the way)). Banging on the door is required for those with lower Passive Perception (ie: deeper sleepers). or opening it and ringing the bell. Same effect.
Again, this has been covered more than once, I believe, if not quite in this detail. I'm not making these numbers up, folks, I'm reading the rules and applying them. And adjusting for the intended muffling effect of walls and doors.
And yet, it keeps coming up. I keep having to go over it. This is part of my frustration with things.