I have done a welcome packet for families that travel with us, which is usally family. In each packet I give an itinerary of everyones flight information and when they are arriving as well as how they are getting to the hotel. As most of us are staying at the same hotel I just list that but if someone is at another i give that info as well. I also give a list of all advance dinning reservations and whose name it is under and what time they should be at hte place, I also give them maps of the parks and the resort. Depending on what is going on and why we are all together, I have made luggage tags, and a spreadsheet of park times, I have also given a list of expense sheet. Also I have given them some Disney dollars, a pen, a pin andything that i can find.
If the family is not traveling with is but I have helped them make all the reservations, I usually give them a map of their resort, a list of the park times and some suggestions.
Good luck