The problem with the deleted data in AZ is not that the files were deleted. That's trivial - just undelete the ones that are fully intact. As to the broken files, rebuild the ldf (transaction logs) files and fix the gaps caused by the broken deleted files. That's rather mundane.
The problem is the zero length files. The actual data that is needed is the adjudication data for 11/3. Notice - those files are both deleted and zero-length. this is bad. The criminal first dropped the database, then deleted the file. When the file is undeleted, it will still be zero length.
The good news is that the database structure appears to be known, so that can be restored. The recovery team would then need to rebuild the database files. This is a very complex operation.
If those machines were connected to the internet isn’t there a good chance these files might have been copied and stored somewhere ? There are a lot of hackers out there who are more than capable of pulling that off.
I doubt you are going to get down the sector-level file reconstruction remote. This is a pretty complex procedure. They would start by making a byte-for-byte replica of the hard drive using dd or clonezilla. Probably you create multiple. Then, you send to a very specialized data recovery team. There are data recovery specialists who specifically have expertise in SQL Server file recovery.
Another complication is that the data is likely encrypted, making reconstruction very complex. Hopefully they have the database access keys.
Thanks! Hope they can!