No, the featured listings slider is by default, only shown on the homepage. I am aware that some customers have made customizations to their theme to do what you suggest though.
By default, site users should be set up as "Contributors" which allows them the edit their own ads anyway. If you wanted to create an ad on behalf of someone, then you could change the ad author in order to allow that person edit access, but other than that, only an admin could edit from the
wp-admin (aside from the original ad author). If you literally wanted to stop people being able to edit ads, you can set this from within the ClassiPress admin, but this applies across the board..not per user. Anything else outside of this functionality, yes, is a customization.