In answer to your questions:
1. Yes
2. Yes you can allow paid featured ads which appear in the slider, Renewing a listing will move the ad back to the front page as it essentially sets a new date (and latest listings are shown at the top).
3. There is no specific "urgent ads" feature within the theme.
4. There are no highlighted ads, only featured ads for the slider. There are existing ClassiPress child themes such as
this which do offer more features ad options such as highlighting as described.
5. Yes, our themes are responsive and can be viewed on any device. Thanks.