I have the same problem.
When searching for objects / accesories from the Floor/Wall/Roof Accesories in the Interior Wizard, nothing is show up.... but I mean NOTHING.
The problem was that I didn't included the Accesories Library 20 in the Library Manager. Fixed after Adding it.
However, this tool as many other, doesn't instantiate a new grouped object containing all others, but instead contaminates your zone with a lot of objects.
Floor, Wall and Roof finishes gets into the floor plan as separated objects, this makes harder to make further changes to the house, since the floorplan is poluted.
I have for example, created an overall structural slab for each story. And finishings will be made if this kind of zone-related objects. This way I can add Tiles or parquet depending on the zone. However the instantiated object is not a simple slab, is a full intricated floor construction profile.
A change to the tile thickness will not update the wall finishings.
I find it a less robust solution as I expected.