Carrie:
You know your children and what they can bear. You didn't mention your children's ages, but if you want to view the fireworks after the evening parade at the Magic Kingdom, and that interrupts their usual bedtime, I would only do that if you are willing to leave the park for a nap in the afternoon so everyone, including you and the folks standing around you, can enjoy the fireworks.
On the other hand, if you find that a later dinner is best for your family at
'Ohana, you can either enjoy the fireworks while dining at the restaurant (they pipe in the choreographed music!) or after dinner at the Polynesian beach. Keep in mind that as that resort currently undergoes updating, your view of the fireworks from the beach may be compromised. On our most recent visit, walls had been erected on a portion of the beach, although we could definitely see
Wishes. Crying, tired children become the memory you'll take home rather than the beautiful fireworks if you don't pace yourself, whether you eat dinner and enjoy them or head back in the parks. Either view is lovely and creates its own special memory, although inside the park is definitely louder and brings a crowd. As Jiminy Cricket says, "Let your conscience be your guide."
Wishing y'all a magical vacation!
Whitney