Typically frames are made of wood or metal. For a canopy, there needs to be fireproofing. All structures must meet building codes. If there is a second tier, there is a limit on the number of people that can occupy the space. Speakers are generally not concealed.
Wires run under carpets, which becomes problematic.
Another option is to wire from the ceiling or from the track lighting. Then the wires are run along the tops of walls or panels. 3 months minimum. It depends on how custom the exhibit is. A Practical Guide for Temporary Exhibitions.