If you're not looking for character meals, then CRT is probably not worth it. The food definitely isn't stellar and the price is pretty high. I'd go to BOG instead. Food is better, you get to see more of the castle than at CRT, and the atmosphere is way cooler/more interesting. It can be super tough to get a reservation there but if you can, I think it's worth it. Do the dinner, not lunch though.
Biergarten in Epcot was a lot of fun for our family. Gorgeous and authentic inside, good food for buffet food (the pear dessert was one of my faves of the trip!), and entertainment with a dance floor. Our daughter is younger than your kids (5), but she had a blast.
If you're looking for a splurge on price kind of experience, Hoop Dee Doo Revue was a lot of fun and people seem to recommend it constantly. The show is a lot of fun for all ages and the comfort food is good. I still think it's pricey for what it is, but then, it's Disney.
It's a lot easier to swallow these on the DP.
If you're looking for a really good dinner that combines fireworks, dining at Rose & Crown Pub in Epcot is a great choice. It was my favorite meal of our trip (bear in mind we didn't do any signature restaurants), and our 7:20 reservation worked out perfectly for getting an outside table that was front row for Illuminations. It's also not nearly as expensive as CRT
I'm not aware of any other dessert themed special experiences.