You don't mention if this is your first trip or not, but personally, if staying at Poly, I would make MK my first park. It's hard to resist as it's right there!
You may want to check a crowd calendar, like touringplans, to see the estimated crowd calendars for each park on each day to give you some guidance. Have you decided which parks you want to go to? How many days per park? If not, I would think about that OR even consider going to each park for the first four days and then scheduling the rest of your park days from there. If this is your first visit, you may also want to reconsider the water park option. The Poly pool is lovely and they have a splash pad for the kids. If you decide when there that you want to go to a water park, it's very easy to add that option back on.
I, too, would recommend planning that resort day for day 4 or 5 of your trip when you might be a little tired of touring. You could also use that day to re-group and decide what you want to do for the remaining days of your trip (or re-configure your plans) to see new things or re-visit some favorites.
As far as dining reservations, I would plan around your park plans (maybe take a look at some in-park restaurants) or your resort. I wouldn't recommend any restaurants that will take you too far afield (for example, I wouldn't eat at Cape May for breakfast on an Animal Kingdom day).