Hi, Lisa!
Each guest will be able to book their
FastPass+ based on their check-in date. For those of you staying at a Disney Resort hotel, that will be
60 days prior to arrival. Since you are one day later, you will be able to book just one day after your travel pals.
Since you are doing all the travel planning (by the way, I know that it is a LOT of work, so thanks for all your efforts) you may just want to wait until your booking window opens so you can book all the FastPass+ times together. This will make your life much easier, and that one day really shouldn't make that much of a difference in your time/attraction selection.
It sounds like you have the system figured out, but in preparation of booking your FastPass+, make sure everyone has their My Disney Experience account, linked theme park tickets, and that you are all connected through your
My Family & Friends List.
With a large group, you may want to
book some fun dining locations. A buffet is usually a good choice since there is a variety of food so there will be something for even the pickiest eaters in your group!
Have fun being the designated travel planner, and I hope you get all your first choices for your FastPass+. Good luck!
Cathy