OVS-ES vs Microsoft 365 E3

RobM86 The Microsoft 365 A3 + A5 bundles will cover everything in your OVS for your users, providing you have the OVS-ES "Desktop pack" or equivalent. So Office, Windows + CALs. Some useful information can be found under the "Compare plans" link here:

https://www.microsoft.com/en-gb/education/buy-license/microsoft365/default.aspx#

and I have also attached a useful Office 365 vs Microsoft 365 comparison chart.

Your Office 365 ProPlus license will have come with your OVS-ES agreement. Without an OVS, education institutions get standard A1 for free, but with OVS you will have A1 Plus which includes the office suite license, whereas A1 is restricted to web apps only.

It sounds like you will most likely go for the CSP licensing model. However, depending on the size of your tenant, an EES agreement could be more beneficial for you. EES requires a minimum of 250 users and effectively gives you the ability to purchase cloud and on-premise licenses under the same agreement. Whereas purchasing any MS Server licenses is not doable under a CSP model. The pricing can also go down depending on the tier of EES you qualify for. Here's the EES program guide:

http://download.microsoft.com/download/8/9/A/89A3F8B9-94DE-4956-A56E-F6D2B215D0E6/Enterprise_Agreement_Program_Guide.pdf

Hope this helps.