If you have more questions, please contact the IT Support Centre by calling 613-533-6666 during regular business hours, or by filling out the online help form.
Viewing your calendar from your mobile device is one of the advantages of the new calendar; however, the software client application running on your device may not be fully compatible with Outlook and should not be relied upon to process meeting requests successfully. If you do accept a meeting request, do not delete the request from another computer (such as a mobile device) because the meeting may disappear entirely from your calendar. Do not use your mobile device to process meeting requests for yourself or as a delegate.
Chances are it's because you didn't actually send the invitation. Outlook calendar is reliant on sending an email in order to register your response with an account. If you create a meeting, or respond to a request, make sure to send an email notification or your response will no be received.
It sounds like you'll want to make your colleague a Reviewer of your calendar. This means they can see the details of your calendar but don't have the permissions to change or delete anything. You can assign them the Reviewer role through the Delegate Wizard. See these tutorials on appointing a "reviewer" role for a delegate:
Unfortunately delegation cannot be done through Outlook Web App
Meeting attendees can only see who has been invited to a meeting, not RSVP's. If you are an attendee and would like to see who will probably be attending, open the meeting and then click on "Scheduling Assistant". You can use the legend to make an educated "guess" as to who will be attending.
Exchange Distribution Groups are requested by the IT Admin Rep. When the IT Admin Rep requests the group, a primary and secondary group owner can be identified. Group Owners will be able to add and remove people from the group. To request an Exchange Distribution Group the IT Admin Rep should complete theGlobal Address List (GAL) Distribution Group Request form available from the IT Admin Rep's Restricted Resources page.