California Grill is one of the nicest restaurants in WDW, with one of the best views (in Contemporary resort overlooking MAgic Kingdom so you can see the fireworks from there) and it's also one of the most expensive. And while my kids happen to enjoy it...mainly because they know how much their mom and dad love it...I don't know if it's the sort of restaurant a 7yo would appreciate as the last meal at WDW. Although if you can book at a time when the fireworks happen, I'm sure there will be no complaints. And if you eat earlier than that, no worries, they do let you back into the restaurant to watch from the balcony if you want.
Over at Epcot, the Rose & Crown has patio seating. If you're lucky enough to snag a seat outside with later reservations, you'll have a great view of their fireworks spectacular. And like California Grill, if you dine earlier, you can go back to the patio area when it's time.
It might not still be going on when you're there, but Animal Kingdom has restaurant "packages" that include special seating at the Rivers of Light nighttime show. One of those restaurants is a character meal - Tusker House - and it's a great buffet.