It is now possible to anonymize you data in Apple School Manager, this is done by simply enabling "Anonymize uploaded users" in your SFTP upload settings. What this does is instead of sending the names of your users, it will create users in ASM based on numbers. When you sync your data back these numbers are linked to the users.
More information about how to add users can be found in this article
Your shared iPads will still display the names and photos of your students because this is stored in Jamf School.
We've also made a simple flowchart to show you how this is done.
For more information about privacy please read this article.