I write this to you as a Canadian Citizen. Yowser!
ECAS went to Decision Made on December 25.
Received Invitation to appear at the Ottawa office for Ceremony by email on January 13 - ceremony scheduled for January 31. The invitation did not speak to the number of guests you could bring.
The Invite said 8:30 am. This gave them time to process everyone in by the 9:00 scheduled start. I brought all my passports current and expired, my PR card, and my IMM 1000 Record of landing.The check-in person collected my PR card and stamped my IMM 1000 to indicate I'm no longer a PR.
I retain my US passport because they are snippy about Americans only entering on a US passport. I will go to the main passport office in Gatineau to expedite my new Canadian passport so I can reenter Canada if I leave. My job requires travel outside of Canada on short notice to I need to do that quickly.
I took my wife and two adult daughters. There was lots of room for guests. There were 90 new citizens from 32 countries. The ceremony took about 90 minutes. Plus time to get your picture taken with the Citizenship Judge if you want.
I'm relieved to have this completed.
Good luck to you all.