I am in the process of refreshing a dev farm from production. Typically I do this with database migration approach. I treat services DB's the same as the content DB's. I will take a backup of the database in production SQL and then restore the DB in Dev and go through the mount process (for content DB) and recreate the service with the restore name of the DB for the services. This works great for the content DB and the Managed Metatdata, but the Search is not happy at all. I thought I have used this process in the past on search, but it just is not doing what I expect.
When I create the search service with the existing database, I get the error that the Database contains User-defined schema already.
I decided to simplify my testing and I create a completely new/fresh Search service and deleted the search service, leaving Data intact, I run the powershell to create the search service with those DB's and I got the same error.
I have cleared SP Config cache, restarted the server, etc.