Hi, i'm planning my renovation. would like to ask, sometimes i visit show rooms, noticed they built feature walls in master room, with functions to hide the door to the closet.

With regards to these feature walls, are they applied on an existing brick wall/ plaster wall? or is it a hollow wall, something similar to a plaster wall?

Is it possible to install wall sockets or drill nails to hang picture frame on these feature walls?

Who should i engage in terms of these feature walls? (Carpenter? Plaster ceiling guy? wall panel companies?)

Is this more expensive than build a new sand brick wall?

Thank you.