Buy it now will only appear if someone sets on upload to allow buy it now. You can edit your uploadproduct template and remove the html for buy it now and then future ads will not have buy it now. As far as disabling payment just set no in edit usergroups for all groups. Feedback is only allowed to be left by registered users. The feedback link is emailed to users who have won actions etc. Guests are not allowed to leave feedback and a user can only leave feedback once.