Can a Team display a calendar in MS Teams? 

No. Only Outlook can display the entire Team Calendar. 

Can a Channel display a calendar MS Teams?

Yes. By adding the Channel Calendar app to a Channel one can see a calendar. To add events or meetings to this calendar one must add it via the Channel. Once added to the Channel. It will appear in the Channel Calendar and the same Teams Calendar in Outlook.

Why can Outlook display the calendar in full but not the Channel Calendar?

The Channel Calendar is only for that channel. But the actual calendar items are stored in the Team Calendar. Channels filter out items not for their calendar.

What are the ramifications?

1. To see the full Team calendar one needs to view it in Outlook

2. Adding an event in Outlook to the Team Calendar saves it without Channel information and thus it has no channel to display in.

3. One needs to add calendar items to the channel for it to appear in the Channel Calendar.

4. Calendar items added without invites are treated as events and users should not get invites. But they may get a notice an event was added as a member of the Channel.

Could it be possible?

Not with the Channel Calendar App from Microsoft. But a developer might be able to create an app to do this. I will need to do some research for an add on.

Research

Look for the subheading, "Things to know about channel calendars" at...

https://support.microsoft.com/en-us/office/see-all-your-meetings-in-microsoft-teams-cebd0b41-5cab-42bd-a6dc-bca46bda7b35

Discussion on people's experience with the Channel Calendar App.

https://techcommunity.microsoft.com/t5/microsoft-teams/add-an-event-to-channel-calendar/m-p/2109754