@Judes2 you were sent the email on August 12 and again today. You can view it (without team specific info) here: https://mailchi.mp/28d7e692f494/mouseadventure-player-information-saturday-event-831989
You can review your team registration under your profile on these forums.
The upstairs area will generally not be accessible to anyone except players during the event. We cannot guarantee security of items left upstairs if there is anything valuable.