I know when we had our rehearsal in october, I had family there. Ours was pretty informal though, we didn’t go to a resteraunt, we had catered stuff at my Mom’s house. But I think that as long as it’s okay with your brother and sister-in-law-to be there’s no reason why you shouldn’t be there for them. And Kudos on the ordering the most expensive thing! That’s something I would do, cause I can be devious like that!! 😆 😈