There are lot of options to access data in UC in fabric either by mirroring or by creating shortcuts on the ADLS. 

But there are limited options the other way round. Currently there is no way to access the fabric objects directly from databricks. One option is to try to create external location on top of the data lake where the fabric tables reside and create delta tables in UC. The other option is to create federated queries from Databricks. You can try out this option.

https://murggu.medium.com/running-federated-queries-from-unity-catalog-on-microsoft-fabric-sql-endpo...