Hi, Glenn Maxwell
Based on your description, I understand that you want to query the number of meeting invitations and the status of the deletion operation.
After my testing, in compliance search we have that option.
The syntax you provided is correct. I successfully deleted the meeting invite. The status after a meeting is successfully deleted is completed. You can use command Get-ComplianceSearch -Identity "TestDelete" | Format-Table Name, Status to view actions that are in the status of the deletion.
However, there is no official documentation on how to query the number of meeting invitations at this time.
If my answer is helpful to you, please mark it as the answer so that other users can refer to it. Thank you for your support and understanding.