My villager trading hall is set up so that each villager is separated by a wall and has a 2x2 area. 2 of those spaces are filled by the bed and 1 space is taken by their workbench. To make sure they don't die when waking up, the room is three blocks tall, so the villager can stand on their bed. On 3 sides there are solid walls, but on the 4th side, where I peak through to trade with them, I have a row of iron bars on the bottom, empty space in the middle, and solid blocks above. My villagers are somehow hopping up onto the iron bar and walking through the empty space while it's head is inside the solid block.