Everything is basegame compatible except the plastic decoration box that requires Seasons DLC
The Attic ladder requires RVSN Uplifting elevators mod to be functional: The Sim will be teleported upstairs or downstairs (without animation, it works like my spiral stairs), but they will autonomously use it when asked an action on a different floor.
Notes
You'll need to toggle bb.moveobjects mod to place the top and bottom part of the ladder.
The bed has no cover, which means some animation will be a bit weird (when sleeping, the feet are clipping through the mattress and the woohoo action is definitely NSW 😂)