I'm not a proponent of the
DDP. We've always gone OOP and spend less, overall, because of our eating preferences. It may be a good value for you with two kids and character meals, though, so it's worth it to compare costs.
We've only ever done pre-park opening breakfast. Mornings are the slowest time during our touring and we value shorter waits over TS breakfast.
Our first trip was at the Poly. We really enjoyed it and the transportation to MK and Epcot was great. You all will have a great time!
Some options on the monorail that are a good OOP value, with generally good reviews
Grand Floridian Café - serves a brunch menu until dinner time
The Wave - breakfast offers a la carte and buffet. Also serves lunch and dinner.
More expensive but food reviews have improved recently is 1900 Park Fare, both breakfast and dinner. I like how easy it is to get to GF from the Poly. My kids think the monorail is an awesome ride - lol!
Akershus is a decent value for a Princess breakfast and my kids enjoyed it. Even my two boys! I like that platters are brought to the table.
Via Napoli is great for splitting a big pizza and one of my favorite places
Garden Grill is a popular character meal with Farmer Mickey
At DHS we enjoyed 50s Prime-time and Sci-Fi. My kids voted for Sci-Fi for our upcoming trip. The food is ok but the atmosphere is fun for them.
Tusker House at AK is well-liked, but I don't love buffets with small children. I spent more time getting food than eating the food on my plate!
Yak & Yeti was a huge hit with my kids. They shared the adult Lo Mein and ate almost all of the wok-fried green beans.
Sanaa at Kidani is a favorite of mine and we'll be dining there in June. Before dark, you can see the animals on the savanna next to the restaurant, which my kids will love.
Just a few to think about!