I just have a few general clarifying questions regarding API.
Our organisation is partnering with a CRM provider, and we are wanting to take the user generated posts (custom post type) and automatically feed into the CRM system.
I am no expert, but I wonder if you could see a possibility for an API call that could be connected to a database - given that the CRM providor faciliate this on their side?
For your custom post types in the settings you need to make sure the option show_in_rest is checked (it is disabled by default), which will make the post type available in the REST API.
Custom fields can be retrieved as the raw values from the database (if you do not know already, fields are stored with a key that uses a 'wpcf-' prefix, so a Types field "status" would be stored in wp_postmeta with a key of 'wpcf-status', for example).
We don't currently have any special endpoints to return formatted fields, but that may come as we work on deepening our Gutenberg integration.