Help, please: Gallery house/lot with some unusual placements? Is this a build cheat thing?

bb.moveobjects on lets you move and place things completely freely (hold alt while placing to avoid snapping).

For height changes, The 9 and 0 number keys move things up and down when bb.moveobjects is on.

Once things are in place using those, they stay there unless you move/delete them or, if they are on a surface, move/delete the surface. So if there's stuff you want moved you need to do it item by item.