1. There are default ad locations within ClassiPress on the header, single ad page and sidebar widgets - configured in the "Advertising" tab of the
ClassiPress admin dashboard and widgets screen. You can customize the theme to add other advertising spaces and rotating banners if you wish. There is also more than one advertising related plugin available for ClassiPress in the
AppThemes marketplace.
2. The color cannot be changed via any settings for it in the ClassiPress admin, however yes you can certainly change the theme code to modify this.
3. , 4. & 5. Through customization, yes these could be achieved. Our themes are not encrypted so you are free to make changes if you wish.
6. Yes, and there are
other payment gateway plugins available from the AppThemes marketplace.
7. Not sure what you are referring to specifically here, but if you wanted to add a forum to your ClassiPress then this is possible, it's just not built into the theme specifically.
8. You can read more about using child themes
here in our developers documentation.
Thanks.