Top that with contractors that don’t even provide a drawings, plans or official documentation of their intent and we can see where their seemingly in control of the market. Their swagger is even more overloaded when they’re excited to come view your home yet can’t call you back week after week months later because they’re too busy to even consider your meager $30-50k one-room remodel.
As a contractor I can tell you that most reputable contractors probably don't need your job, and if you make things too complicated or troublesome, they will move on to other jobs that don't throw up red flags. Much of what you ask for here is reasonable, but bringing a second contract into the equation can set of some alarms that you may be a difficult customer to work with or even a litigiously minded person who is likely to try and bring a lawsuit whether deserved or not. Anything you want covered should be in the original contract.
My suggestion is when talking to contractor be subtle and ask your questions. Ask if he/she will have a dumpster or trailer to haul away debris. If the don't get dumpster or have a trailer then you probably don't want them to work on your home. Tell them your concern with the only toilet in the house. Unless it is not safe I have always reinstalled the toilet so it could be used at night. A good contractor will work with you in anyway possible because you are the key to more business.
After the tearout, the plumbing and electrical are updated throughout the room to accommodate your new layout and fixtures. Then new backer board and subflooring 1 are put in, followed by tiling, and finally the installation of fixtures, lights, and accessories. From tearout to completion is usually a two to three week timeframe. Costs for this phase of the project range from $45-$65 for a plumber to $65-$85 an hour for an electrician and $5-$10 a square foot for flooring and tile preparation.
There are a wide range of costs associated with remodeling a bathroom, including size, the type of materials, its current condition, and the location. Homeonwers spend on average between $15,000 and $25,000 in their bathroom renovation. For example, the average cost of a 100 square foot master bathroom with tile walls and flooring, new fixtures, double vanity, and walk in shower with separate tub is around $20,000.