Organisation and Person have contact_details fields which is a one-to-one map between a contact and an organisation. This seems competely redundant with the more generic contact list provided at the AIResource level. A contact_details property is also not specified in the meta model.

In a migration where this is dropped, we do also need to safely add current mappings defined this way to their matching many-to-many mapping (e.g., migrate from the contact columns to the link tables).
In the test server, there is currently one contact with a direct relation with an organisation. In production, this is not yet used.

For that reason, at this moment and with the proper migration, I think it is fine to consider this a non-breaking change.