1. To clarify, ClassiEstate is a child theme which is available in the
AppThemes marketplace. It is not created by AppThemes, which is why it is not included in the AppThemes club package (more details about what is included is explained here on our
pricing page). You need to purchase ClassiPress theme in order to use the child theme.
2. ClassiPress includes a custom forms and fields functionality which will allow you to create a custom form based on the category selected, so you can have different "add new" forms depending on whether or not the customer selects "sales" or "rentals". This function is explained further (with video tutorial) in our
ClassiPress documentation.
3. AppThemes does not officially support third party plugins, so we cannot guarantee that such plugins will be 100% compatible with our themes. I'm not aware of this specific plugin being mentioned in our forums at this stage.
I hope this information helps. Thanks.