Do all first class seats break up into in small enough pieces to go through passenger doors, or can they come through the lager hold doors and up through the floor?
All the cabin parts come through the main doors; seats, galleys, lavs. There is very little space between the floor structure to pass items up from the cargo area. A person can fit some places, but not things like seats.
I always hated taking things like lavs out. They are really big boxes that barely fit through the door. On narrow bodies ceiling panels may have to be removed so you can tilt the box on it's side. The box tends to be rather smooth with very few good places to grab it and pick it up.
To move lavs and galleys, we used big suction cups like these. You would think they would damage the decorative vinyl on the side of a galley, but the don't.
"Drop zone in 10". Heard later: "Oh wow. Her ranting was sooooooooo distracting, we forgot to give her a parachute". "She did say that she is Secretary of Stat and doesn't need one"................