Just for clarification, Vantage is a theme, not a plugin - so it is not designed to be integrated into an existing theme in the way that a plugin is.
1. Yes, you can make all listings free, thus bypassing any payment requirements
2. Yes, you can allow publishing without moderation if you wish
3. You cannot review your own listings in Vantage
4. You can create a custom listing form in Vantage where you can use the fields you wish, however, by default the map and contact fields are still there. It would require some customization of the default theme on your part if you wish to remove these. Thanks.