Long and hard struggle behind. Now in use but we have still some serious problems.
We have 24 shared-mode ipads. Meraki as MDM with manually entered 7 classes and 150 students for Classroom configuration. ASM import did'nt work and as teachers use their own appleid:s manual configuration is the only way.
Owner of ipad have to be appleid witch belong to every configured class. This is only way to see classes in login. So owner of all 24 ipads is one of the teachers.
Problem: Every time a student log in it changes ipads owner to students appleid. Then next student can see only previous students class. We have to manually change ipad owners back every time they are used. Students can still log in with entering their appleid:s but it breaks the whole idea.