Helicopters can fly higher than 30 feet. Baby Godzillas would not be trapped in the entry way of the Garden by glass doors. That fish in the basketball hoop was still alive. He must've been out of the ocean for over a day at least. Lazy-Eye Larry was firing the Apache chain guns.
Sidewinders blow up on proximity fuses.
They wouldn't have kept going. Sidewinders have almost no explosive force. They're meant to pop aircraft, not cause major structural damage to the Chrysler Building. The devastation of Chernobyl caused earthworms to increase 17 percent in size. That's a lot of nuclear testing to make Gojira that big.