Code Question - Non-loadbearing wall

It appears the builder of our mid 80's house decided to wallpaper the bathrooms right over the sheetrock without any primer and as you can imagine this made for a major pain to remove the wallpaper. Now that it is done and we have beat the heck out of the walls, we are wondering what's the best next step. It looks like we could try and skim coat the walls or remove the drywall and install new or install a thin drywall say 1/4" over top of the existing walls. Is installing a thin drywall over that existing that was beat up from wallpaper removal considered an acceptable practice? We are going to sub this out and certainly it will make it easier for the drywaller to not have to remove the old before installing the new. But I know, easier isn't necessarily better so that's why I'm asking the question. Thanks for your replies!

My husband and I had recessed lights installed in our family room ceiling. In order to run the wires, the electrician had us cut strips of drywall out of the ceiling. My husband has replaced the drywall and used joint compound with tape. He sanded the entire ceiling and then rolled on diluted joint compound to create texture. It is now dried and unfortunately the repaired areas are very visible bumps. Also, he took down some fake beams and when removing them a thin layer of the old ceiling peeled off. Those areas are also visible through the joint compound. The question is what should we do now? Do we need to do more sanding or should we go ahead and put a coat of ceiling paint on in the hopes it will cover up the bumps? Thanks in advance for your help.