Hi Kristine!
Clearly, we need to make sure you have a magical evening on this particular night!
If I am understanding your question, it sounds as if you have separate reservations for Cinderella's Royal Table and the
Fireworks Dessert Party at Tomorrowland Terrace or the
Fireworks Dessert Party with Plaza Garden Viewing (note that this one is standing only). First, be sure to check the time of the
Happily Ever Fireworks show for the dates of your visit. When I checked, it looks like the show is starting at 9:00 p.m.
The benefit of the dessert party is that you have lovely snacks with beverages along with a reserved area from which to watch the show. Having viewed the fireworks from this area, I would say that it is not my favorite view, especially with little ones because it is more difficult to see the detail in the projections on Cinderella Castle.
With your 7:00 p.m. advanced dining reservation at Cinderella's Royal Table, you would most likely finish dinner and leave the restaurant just prior to the show, so you could potentially have a difficult time finding a viewing spot. Although you can see some of the fireworks from inside the restaurant, the view is not the best and your ability to see anything depends on your table location in the restaurant. Plus, you would miss the projections on the outside of Cinderella Castle.
Our fireworks tradition is to settle right in front of Cinderella Castle, to the left (if you are facing the Castle), just before you get to the special walkway that takes you through the Castle. In the past, a Cast Member has started standing in front of a taped off area in this location about an hour prior to the fireworks show. We always check with that Cast Member to make sure we know where we can stand. The beauty of this spot is that no one can stand in front of you since the area is roped off right where the Cast Member is standing. So, if that spot is available, your little ones should have a great view.
Since I have twins, I will also say that loading my girls up with desserts just before bed time was not what I would have preferred to do when our girls were the ages of your little ones. If you decide to cancel the dessert party, I would also suggest that you try to modify that dinner reservation to an earlier time - 6:00 p.m. or 6:30 p.m. You would need to be out of the Castle and in your viewing spot by 8:00 p.m. to secure a decent viewing location.
Kristine, keep in mind that the viewing location I have suggested is quite close to Cinderella Castle, so there will most likely be a lot of people behind you once the show starts. As it gets closer to showtime, it gets harder to navigate the crowds, so make sure everyone has made a visit to the bathroom by 8:15 p.m. (if the show does indeed start at 9:00 p.m.). Afterwards, you will need to navigate the crowds to leave the park, so just be patient.
Wishing on every star hoping you all get to see the Happily Ever After fireworks and projection show. One final suggestion - make sure everyone gets a nap on the day you plan to see the fireworks. I have seen many a little one fall asleep right as the show starts!
Magic and memories,
Donyell