Re: Change name of Corporate mail folder to "Desktop"
For me (If I understand it correct what you want to do), it does not look that this will help you, because, this only applies to Blackberry Handhelds Version <5.
You could try to remove the icon, but I dont think this will change the devices behaviour to show a separate Inbox and the Desktop icon it the device software is 5 or later. Even it the icon is removed, there will be no "Desktop" icon, but only the Inbox.
Your problem seems to be that the "Desktop" icon is called "firstname.lastname@example.org", which is normal for any BIS mailbox, and as it seems to me (no experience with O365) normal for Office 365.
The only thing I could think of is:
All users have to manually hide the "Desktopemail@example.com" icon on the home screen
Go into the the inbox, open options, inbox settings.
Remove the checkmarks for all items but the "Desktop"
Then, the "inbox" will only contain corporate messages.