Ceiling choices?

I have a basement which was previously finished. I am looking to change some walls. The basement gets a musty smell sometimes. I read somewhere that putting a vapor barrier and insulation between the outer wall and the sheetrock will take care of this. From reading other posts it appears that you are to put the insulation between the furring strips and a plastic barrier on top of the insulation which will lay behind the sheetrock. Could you please let me know if this is right or if I have this a little bit backwards. Second, question I am looking into putting a half bath in the basement as well. I have heard that I may have to use a special toilet for this as it is below the ground. Can you offer some advice on how to go about. Third, with regard to the flooring. I do not have a problem with flooding but was wondering if it is a bad idea to place padding under a burbur carpet for a basement. What ever advice you can offer would be greatly appreciated. It is a little bit overwhelming trying to plan everything out. Thank You

I'm finishing my basement and decided to use steel framing. Most of it is pretty simple but I am at a point now where I'm not sure what to do. I am using the existing wood floor joists to hang the drywall for the ceiling throughout the basement except in the bathroom, where I want to lower the ceiling a few inches due to ducting etc. in the way. My question is, how do you hang ceiling joists on steel studs? Are there special joist hangers or do you just notch the joist and screw through the webbing? Do I need to use special steel joists for the ceiling or can I use the standard steel studs? The span isn't very big, only about 7 feet at the widest. Any help is appriciated.