The instruments do not automatically stay atatched to their positions, you have to move them manually. They will default to the height of the lighting position they are placed on.
When you make your lighting position, create the geometry at Z=0. When you convert the geometry to a lighting position object, set the Z height of the lighting position object.
As for the underhung and overhung lights, you will need to make a duplicate symbol. Take your existing symbol, duplicate it, edit the 3D part of the symbol, then in a side view rotate it 180 and re-align the insertion point.