Hi, Lynton. Thanks for your interest in our plugin suite.
The free/core The Events Calendar plugin has a read-only REST API (full CRUD functionality is planned in the future). With read-only access, you could still copy data in some fashion, although you could do that with MySQL too.
Our Event Aggregator add-on can pull events from Site A into Site B, if both sites are running the free/core The Events Calendar plugin.
Anything other than this would be in the custom development realm, for which we don’t provide support. If you need some coding help, you may want to ask your developer or reference our documentation and list of known customizers.
Last but not least, we have a pretty great Refund Policy so you can buy one or many of our add-ons and thoroughly test them.
I hope this info helps. Let me know if you have any follow-up questions.