While it’s true that being fashionably late to a party is traditional, if you haven’t read Strange Bedfellows go back and do so now, as it features the guest list.
When I’d been a player in this module the lady playing Pernicia spontaneously decided mid-module that the bride’s dress was missing–and this got a lot of characters worked up. I stole that idea for this run. I thought that, as the GM/NPCs, I would have to come up with all sorts of things to go wrong during the wedding planning. Boy, was I mistaken. . . .