this shows the two rectangular holes that go to Thea's room and the living room. I stuffed the area between the studs above the registers of all floor penetrations w/ rockwool and used quite a bit of fireblock foam wherever it seemed appropriate.

You can see one pipe going over the wall into the fireplace room. I stuffed/compressed 4" rockwool in the gaps between joists going over this wall, including around the metal duct pipes. Everything is FAR better now than it was, if there were to be a fire in my house.