We have a hybrid deployment with 365, using the free hybrid edition license key for Exchange provided by Microsoft, through the Office365 portal. As such, this single Exchange 2016 server cannot host mailboxes, and is not involved in mail flow. The primary reason for having it, is easier management of Exchange attributes on our objects, which are syncing to 365 using AADC.
As we created some shared mailboxes before this was deployed (AD user objects synced to 365, given a license, converted to shared mailbox, then license removed), they do not currently appear in the Exchange Admin Console.
If I create the shared mailbox through EAC, sync the user object to 365, and then migrate the mailbox from on prem to 365, it shows up correctly in both places, while being hosted in cloud. I don't know if we are actually allowed to do this from a licensing point of view however.
What I would like to do now, is get our existing shared mailbox objects into Exchange Admin Center, without having to migrate them to on prem, and then back to cloud.
Can anyone tell me if it is possible to get these objects into Exchange, perhaps by changing attributes such as the msExchDisplaytypeDetails or msExchRemoteRecipientType?