Currently we work like this (still tweaking our ways )
Input for Layout is storyboard/animatic, character rigs, sets (usually just proxy versions for speed), props.
Layout artist, takes all these and prepares scene for animator. Imports all geometry, places correctly, imports sounds etc. Most importantly set's up camera which should be as close to final as possible (animated, camera shake, etc). In this step we sometimes do some very basic animations mostly related to set. A lift moving up for example.
Publish from this step is .ma or .hip scene which ready to be animated, plus usually camera and proxy geo in it's place, in case we need to some 3d precomps. This scene also serves as rough proxy (in terms of floor and object placements for set dressing)
In full CG scenes we rarely skip layout, mostly because our animators are often ex-2d animators and tend to struggle with anything even slightly technical.
Practically no sett dressing is done here apart from things that are essential for animators to see.
Layout artist if for us ideally a generalist junior to mid, with good cinematic eye because of the cameras. There tends to be quite a lot of very simple modelling involved.
Set dressing can then happen simultaneously with animation because it uses the same input scene and builds on top of it. If set is done or half done, animator can reference dressed scene towards the end to make sure there are no problems with contacts and such, but that doesn't happen often.
To sum it up.
We almost never skip it, it's mostly about general scene layout and camera. It allows animators to focus on purely animation.