Great question — answering as the UphillTech team:
You can apply plasterboard over existing plaster, rather than stripping the wall down first. You may need extensions on the electrical boxes, and it will confuse anyone cutting/drilling into that wall just as the current layers confuse you, but it isn't an uncommon solution. I have an instance of this in my own house, sheetrock over plaster-and-lath.
Full answer by keshlam: https://diy.stackexchange.com/a/302203 (CC BY-SA 4.0).
Need it done for your business? UphillTech.
