You're staying at the Grand Floridian? Awesome! We did that last spring. I think it spoiled me for staying at any other Disney hotel...
www.easywdw.com is the best Disney blog IMO. I think the DISboards are a bit overwhelming. Josh (author of easywdw) does a really nice crowd calendar, so you can easily plan which parks to do on which days.
Make your dining reservations as soon as possible. Everything else (fastpass+, what to pack, etc) can wait.
If I were you, I'd take full advantage of staying at the Grand Floridian, and try to do as many things there as possible. They have great character meals at 1900 Park Fare, right inside the main building. Eating at the resort is going to be so much better (less hectic, higher quality) than eating in the parks.
If I had to do things over again, I'd eat at Narcoosee's more than once during our stay. It's relaxing, has a great view, and is an easy stroll from your room at the Grand Floridian.
Hoop-Dee-Do would be so much fun with your girls. It's a dinner show over by Ft Wilderness. I tried it for the first time this year. I was a bit worried about it being too corny, but it was a really fun family experience.
have fun planning!!