In regards to the tickets, when we did this ( people coming at different times) I booked everyone with 2 day tickets to get the FD package, and then everyone upgraded their tickets there, to the amount of tickets needed. Since we had one person coming late and two people leaving early, this made the most sense so no one wasted any tickets. I'm kinda surprised that Disney would allow people to be added to a dining package after check-in without dining, since isn't that one of Disney's strict rules: everyone in the room has to be one the same dining package for the same amount of nights? I can see this being a loophole that some families would use, especially those with kids in the junior age group 10-13, who have to pay for adult dining, but wouldn't eat enough to make it worth it.