1. Yes you can create, remove, delete categories.
2. Support is provided through the forum only on which you are given access once you purchase the theme.
3. There is no limit on how many ads you can post. There's no set limit for the membership packs either.
4. If you are not modifying the look the theme, you can simply upload a logo. A basic knowledge in php, css, html and java script with will definitely come handy in modifying the look of the theme.
Please help our moderating team work more efficiently by not sending us support questions via PM. You can read more about how AppThemes support works
here. However, you can send a PM to follow up and remind me if I missed your support request/thread.
Thank you and have a nice day.