Hi Heather!
Planning that first Disney trip can be both exciting and nerve racking can't it? Just so much to choose from! Well hopefully this will give you some guidance...
When choosing the Magic Your Way Tickets, for our family we generally always add the Park Hopper option. You'll find it cool being able to "hop" from park to park on any given day of your stay. To break it up some, we'd start the day at, say, Hollywood Studios, take a little break in the middle, then finish the day at, say, Magic Kingdom for the Wishes Fireworks or something similar. This certainly amps up the "cool factor" for the kids, who on the first trip may try to visit them all in one day (which I don't recommend-smile).
For family dining, I'd go with the Standard Dining plan, which entitles each member of the family with 1 table service, 1 quick service, and 1 snack per day (except for the 1 year old, who can share off an adult plate). Plus with large families, any savings is a plus, and you actually save yourself 30% compared to paying each meal and snack out of pocket. With the table service, you have to reserve one or two character meals, which your children should love (Chef Mickey's and Crystal Palace are good family favorites). Click here for extra details on the Standard Dining Plan.
If you get the Park Hopper, it also makes it easier to plan your meals. So you could eat breakfast one day at the Tusker House (Animal Kingdom), and the evening at Coral Reef (Epcot) on the same day!
Good luck! Hope that 1st visit is overwhelmingly magical!