1- Use it as you normally would. Avoid hitting the redline for the first 1000kms. New cars come more or less with broken in motors.
2-Look to your manufacturer recommendations for this. The first few oil change intervals would be advised to you by the dealership. You will have to strictly follow their plan in order to maintain your warranty.
3-Again, use whatever grade and type oil the manufacturer recommends. They know the cars better than we do.
4-As per my understanding, there would be a 25-30% difference between now and once your motor has done 3-4000K. Just stick to your maintenance schedule, keep everything in check and you will achieve optimum gas mileage.
5-I believe these cars already come with under body coating.Look for a rough black material on the underside of your car.
6-There is absolutely no need to change either the battery or the tires. This is a new car, you should not be replacing things at this stage. These are your run of the mill city commuter cars and not high performance exotics. How can battery residue corrode the car body? I have neither have ever heard of this nor have seen this anywhere.
7-Your call on this. Depends on where you live. If you have a place where you can wax and keep your car clean, then the glass coating sounds like overkill.
