Be aware that California Grill usually has a special event on July 4th that costs around $200 per person.
If you want to be in MK on the 4th, I'd suggest getting there as early as possible and not leaving, because if they close for capacity you won't be allowed in even if you have an ADR inside the park. If your daughter just wants to see the fireworks, California Grill is probably out unless you want to book the special event. I think Polynesian might restrict their beach to resort guests on that day, possibly that is something they used to do but don't anymore. The fireworks can be seen from 'Ohana, but you'd have to have a window table with a view of the castle to see anything. If you want to go that route I'd find out when the fireworks start and book the ADR about an hour prior to that.