Using Classic Outlook on Windows for personal email, calendar, and contact management
So update! I took the risk. I used the old outlook and the "scheduling assistant" option as described above. Added some required participants and moved up some participants who were "optional" to the "required" section and "saved" (or pretty much "save and send update").
I was already added to this invite on my own email but the invite was originally sent from a shared account, so I was doing all this from that shared account. My test for if it notifies everyone then was if it notified me in my personal email. Thankfully I got no notification which means that the "send update" only went to those affected (the new emails added).