Family formals fall apart for one reason: nobody knows who's next. Build the list with real names, handle any family dynamic, and walk in with every combination on paper.
First names only — this is the list you'll call names from on the day.
Choose separately when the couple won't see each other before the ceremony — many traditions keep them apart until then. The list splits into two independent halves you can shoot in different rooms, and the combined shots move to an optional after-the-ceremony group.
Add names above and the list builds itself.