The problem is that you are inserting the image using visual composer which is not the easiest way to replace the featured image and gallery.
The Listing Templates extension was not really designed for customisation as you are trying to do as your needs are more custom than what it was designed for.
The next version has been updated for the new core EPL which does improve it a lot.
However to achieve what you want do the following:
- Disable the gallery like you have done.
- Set the template back to the defaults.
- Template Type: Expanded
- Property Card Style: (Default) Address Right
- Disable the Listing Templates extension.
- Follow this Guide
- Use the contents of the listing template files that you want: Condensed & Suburb Top
- Located in: plugins/epl-listing-templates/content/
- content-listing-single-1-condensed.php
- loop-listing-blog-3-suburb.php
- Inside the content-listing-single-1-condensed.php file you can replace the section LINE 77-87 with
NOTE: Upload your images to the specific listing, this is important for automatic insertion of your slider/gallery.