Please help me decide between two backsplashes

I am doing a remodel on a bathroom built in 1960. The walls were made of a layer of blue board with another layer of plaster. Due to the plaster smoothing out all the imperfections of the framing, the wall thickness varies from 3/4 inch to almost 1 inch. I have gutted the bathroom down to the studs. Now I am looking at uneven studs that with a gap between the studs and the bathtub. Somehow I need to get the cement-board to clear the lip of the tub. How do I do this when some of the studs hit the tub lip and some don't? A few ideas I have thought of is: 1. Just hang 2 sheets of wallboard--the second will for sure clear the lip. 2. Somehow shim the studs to all line up right--I have no clue how to do this so that it will actually turn out right. 3. Nail new studs next to some of the old ones. I am sure drywallers doing remodel jobs run into this all the time--any help would be greatly appreciated! btw the room is 5'x8'

Would like to get a few ideas on what I can do for my basement ceiling. It is a low ceiling.. around 72". The house was built in 1947. I can hear the TV and footsteps above. A few options I have thought about: [LIST]Do nothing and deal with it.. maybe paint the joists Put in a drop ceiling with ceiling max Spray foam insulation similar to retail/industrial businesses - I don't know much about this though. [/LIST] I'm looking for noise reduction and looks. Can I just cut accoustical ceiling tiles to size and glue them between the joists?