Hello,
Thank you for your interest in MyThemeShop.
1. Yes, If you need to add the ad other then the place provided in the theme, then you can easily customize the files there for adding the code. We are providing support for adding ads in header, footer etc.
2. You can use that directly in multiple sites of your own.
3. Yes you can.
4. Sorry we do not provide any such support. You can only connect with us in the forums. We'll get back to you with in 24 hours.
Thank you.