Brunch is on the sea days, with a limited brunch on Key West day for the western itinerary. Assuming Saturday (embarkation day) is day 1, Champagne Brunch is offered on days 2, 3, and 6 (Sunday, Monday, and Thursday).
I'm not sure how they handle High Tea on the Western, but since day 3 is a sea day on either, it should be offered on either itinerary on this day.