putting up bullnose tiles around ceramic tile in bathtub

This may open up a whole can of worms, but I have to ask. We're looking at remodeling a guest bath and a bath in our bonus room (the guest bath is 9' x 5'. The bathroom in the bonus room is 7' x 5'). We're going to have the popcorn ceiling scraped and skimmed, repaint the ceiling and walls, replace the cabinet and vanity, have the linoleum taken up and new tile put down, and re-use the toilets (for both bathrooms). There's also some thin plywood on the subfloor in the bonus bath that we'll probably have taken up before cement board (or similar product) for the tiles. We've gotten a few quotes so far, and they range from $7000 to $14000. Since these are pretty small projects, does it make sense to hire a contractor, or would we be better off hiring individual companies ourselves and manage these two projects on our own? It just seems like a lot of money for the size and scope of work. We've never remodeled before, so maybe that's part of the issue to. We weren't sure what to expect. I removed the baseboard, linoleum, cabinet and vanity in the bonus bath, as well as scraped the popcorn off the ceiling. I can do a lot of the "demo" myself. Any thoughts or opinions are welcome.

Hey all, My wife and I decided we were going to update our kitchen a little bit. We refaced our cabinets this past weekend and intend on redoing the backsplash. There is a tiled backsplash there currently, and apparently it was adhered very well to the sheet rock beneath. When I started to try to remove the tiles with a hammer and scraper chisel, large chunks of sheetrock started coming off no matter how careful I tried to be. I decided to remove the backsplash entirely by removing the top and bottom row of tiles (below the cabinets / above the countertop), scoring just above/below the countertop/cabinets, cutting and removing the sheet rock and tiles. I cleaned up the edges so that they are flush with the top and bottom cut marks. My question: What should I install in place of the sheetrock? I was thinking of replacing it with standard sheetrock, but then got to thinking whether or not I should be using some type of backer board, cement board or something that resists moisture/mold since it can potentially become wet. Additionally, there is not room to tape to the adjacent sheetrock since it is covered by the cabinets above and the countertop below. Do I need to tap or can I just secure it well to the studs? One additional peice of information, one of the walls where the backsplash is to be installed (illustrated in the photo below) is an exterior wall. Not sure that will play a role in this, but figured I would mention it. Also - this is my very first attempt ever at redoing a backsplash and tiling. I still have one additional wall to demolish before I begin to put up the new backer. Your help and comments are greatly appreciated.