Mouran,
Thanks though your answer is not very satisfactory from a customer perspective. No documentation is inexcusable for a professional service.
In summary what one might consider a basic feature of Office365/Exchange services, namely Shared Mailboxes and "proxy" accounts set up as Security Groups are only properly supported by Microsoft for Windows based clients, aka Outlook. Other Outlook clients on OS-X, iOS, etc may provide some partial support, but not sufficient to make the features fully usable.
Put another way, each email account would need to be setup as its own account, using up an Office365 Exchange license to be fully usable across platforms. That significantly increases my Office365 costs.