Did you know that ghosts, after they have cheered at their bed, will stay on that floor until it's time to go back to their grave/urn. So if you want to keep ghosts but don't want them to annoy you, put their urn on the top floor of the house, like an attic, along with their bed and then they won't come down, but you can go up to them if you want.
Also, service sims ghosts will cheer the thing their service is attached to, instead of their bed. For example, one of my sims married the repairman, who came to fix the toilet. When he died, it is the toilet he came to cheer, I'm not sure if all repairmen cheer the toilet or whether it is that they cheer the first thing they fixed. I didn't realise it was the toilet he was cheering at because the bathroom was right next to the bedroom and I thought he was cheering at his bed through the wall. But when the family did a makeover of the bathroom and got a new toilet, he got angry after going to the spot where the old toilet was and finding it not there anymore, and then would float around the house and grounds waving his arms and shouting with a crossed out toilet in his speech bubble.
I dare say firemen are probably attached to the fire alarm, and maids might be attached to the dishwasher. See if you can discover them all.