Custom post type in Pro version

Hi,
I note that the Pro version of The Post Grid permits “custom post types”. I have a JSON feed from a sister site where I need to integrate news content from one site to the other, the feed coming out from my really simple JSON plugin yields an array of WP_post objects as if these have been queried from the database. But notably these posts DO NOT exist in the local database.
My questions:
1. If I pay for the pro version would this give me the ability to pass this $posts array into the Post Grid as it’s data source.
2. I must necessarily start with tests on my localhost, then promote this to a temporary website for approval, and finally push this all up onto the official web hosting once everything is well-proven. Does this imply I will need three licences?
Many thanks for the responses you feel able to give.
John