1) If your exchange setup is based on a hybrid (i.e. part cloud hosting of mailboxes, part internal hosting of mailboxes), for the internal hosted mailbox servers do you still require some form of spam/virus filter for inbound emails at your network permiter?
2) Also, is office365 used purely as the client for the exchange365/online mailboxes, or do/can you also use office365 for the mailboxes hosted on your on-premise servers? Or is it more common to use the traditional client version of outlook?
3) How does authentication to exchange365/online mailboxes work? Is it integrated with your internal AD credentials? Or is there a separate login process?