2. It is the landlord/manager's duty to give you a clearn /ready to move in apt unit start the date on contract.
3. If you can not move the date you scheduled. You can ask the apt to compensate your reasonable loss. They may provide you a temp living place (another unit, hotel) not worse than the unit you plan to rent. And extra cost during moving. Some times a free month may worth it.
4. When you move in, the unit condition should be the same/similar what you saw the demo unit when you visit the complex and sign the contract.
If you get reasonable compensation. It is not a bigger issure. Help other people and yourself, those apt managers are human too and may have mistakes. As long as fixed, it's ok.