It is impossible to say. 5" is a pretty extreme goal. My best advice would be for you to schedule a consultation with a board certified plastic surgeon to be assessed in person. He or she should be able to give you a more accurate response.
Yes it is possible. It depends on how much fat you have and what is more contributing to your increased waistline, if it’s the bony projection, subcutaneous fat or Intraperitoneal fat. If it is the subcutaneous fat, then you can lose inches with liposuction.