No problem, in answer to your questions:
1. By default all users are required to register in order to post an ad. It would require customization of the default theme in order to allow registration-free posting.
2. A change to the current process would also require customization as there is no option to change the listing process from within the ClassiPress admin dashboard. You can however, customize the ad submission form from the admin dashboard so that the relevant fields apply when posting ads.
3. Yes, ClassiPress is not encrypted, so you are free to customize as you wish.
4. Yes, our themes can be translated into any language and there is currently an existing Italian translation for ClassiPress which you can find
here. These are submitted to us by members of the community.
5. We definitely recommend the use of child themes to those who are planning to customize the default theme. Our themes are designed to make use of child themes, so there is no issue with using them. You can find useful documentation
here, and there are existing child themes available in the
AppThemes Marketplace also. Thanks.