Well, Danielle is definitely gonna go. I just checked the descriptions for next week's episodes on satellite TV guide... On the aftermath after the wedding, it says the Mitchell clan is left realing after the tragedy, Ronnie struggles with her grief by conducting a terrible lie, and Archie struggles to get his family back.
Since Archie's still around, he obviously doesn't kill her or end up being the one who dies instead or anything.
I still can't figure out why Peggy would organise a family dinner the week after? Who has a family dinner right after something as tragic as that???