With a 6.5 year old daughter I would skip EPCOT unless the Frozen ride is a must and make Magic Kingdom the top priority. That said, I would also go ahead and get the park hoppers as at that age taking a break in the middle of the day can be a good idea (we still do this with our adult kids!). This way you can visit one park in the morning and a different one in the afternoon. Doing this gives you a chance to figure out if there is a certain park you really want to go back too.
Best pool by far is at Yacht Club/Beach Club Resort. You don't mention anything about what category of places to stay, but with a younger child Animal Kingdom Lodge/Villas is pretty awesome.
For rollercoasters Magic Kingdom has the most with Tron, Seven Dwarfs Mine Train, Space Mountain, Big Thunder Mountain (probably our favorite) and Barnstormer (good for kids). Rock 'n' Roller Coaster will be closed. The most intense by far is Guardians of the Galaxy Cosmic Rewind at EPCOT.
For restaurants our favorite is probably Le Cellier at EPCOT (which by far has the best in park food options). A character meal would certainly be fun with a 6.5 year old (if you can get it this late).
We will be there basically the same time as wtwo3, staying 4 extra days.
We are Disney regulars between Disneyland and Disney World. So feel free to ask questions
