Hi again, Christine! I really think you'll enjoy
Cape May Cafe, and will find the Ferry ride to Hollywood Studios to be an extra treat. As far as your dining question, you'll really want to sit down and decide for certain where you are going to want your Advanced Dining Reservations to be. While I can understand your desire to have a "back-up plan", you aren't going to want to double-book these for several reasons.
First and foremost, know that everyone who goes to Disney wants their trip to be Magical. Disney Dining is often a big piece of the Magic. If you hold 2 spots at 2 restaurants, you are essentially taking up a spot that some other family could be using to create their memories. On any given day, there are numerous families who want to be able to secure a reservation for a meal. It's really only fair that each family choose one restaurant per meal, and not double book. It prevents others from also enjoying a piece of the Magic.
Secondly, I have personally been told by Disney Dining that if it is discovered that you have double booked your reservations, you are at a risk of having both reservations canceled. Instead of having a back-up plan in place, you could instead end up with no reservation at all.
I'd recommend that you sit down with your daughter and go over your dining itinerary. See if she has any strong feelings one way or the other about any of the meals. I have a DD-almost 8 and know how opinionated little girls can be sometimes ;). Maybe let her have a say in the final choices, so she'll be more apt to be on board and excited about the plan.
Hope this helps. I'm sorry the answer might not be the one you were hoping for, but I wanted to be honest. Please let me know if I can help you further with your planning,
Kaylene