Yes, it is possible to upgrade Windows 10 Pro to Windows 11 for education institutions, provided that the devices meet the minimum system requirements for Windows 11. If the PCs were originally licensed with OEM Windows 10 Pro and have been properly prepared for cloning with Sysprep, they should be eligible for the upgrade.
Regarding the redistribution of Windows 11 Pro licenses, if the education institution has a valid CSP license for Windows 11 Pro, they can re-distribute it from the rebuilt master image. However, it is essential to ensure compliance with licensing agreements and that the devices are properly managed under the CSP agreement.
It is recommended to verify the specific licensing terms and conditions applicable to your situation to ensure compliance during the upgrade and redistribution process.