My DSis and her family (2 adults & 2 children) decided to join us for our trip in November, but we get there a day earlier then them and they are staying a day later. We are staying on points at the Poly and they are staying at CBR with FD. We are flying and they are driving as after WDW they are visiting her husbands family in Miami. Now that you have the background, my DSis asked what would be the implications if my 2 DNephews flew down with us? I actually like the idea of spending some extra quality time with my 2 favorite little men but we want to go to MK when we arrive. Since the boys are technically on DSis's package with tickets would we be able to use their park tickets a day earlier than their check-in? I know they can't get use their meals until my sister checks in the next day.