There is no difference in the installer for Xeams Community and Enterprise Edition. It will run as if you have purchased the Enterprise Edition for the first 30 days. It will then get converted to Community Edition unless a license is purchased.
Since you're planning to leave AD on-prem, configure Xeams to use that AD. I assume you will be syncing the on-prem AD with O365. In that case, everything should work fine.
