Hi Daniel!
That sounds quite “non-commercial” to me, so the easiest thing to do in your case would be simply to submit this on-line form asking for the migrators, and one of my colleagues will review the application once OpenNebula 5.12 is out, and contact you: https://opennebula.io/get-migration/
As for the “opencore switch”, don’t worry because the Community Edition is a full-featured version of OpenNebula, released under Apache License 2.0. What the Enterprise Edition brings along are additional bug fixes developed by OpenNebula Systems and software patches with minor enhancements. At the end of each maintenance cycle, we contribute those additions back to the Community Edition, so that EE and CE are in sync for each new Major/Minor release 