Dany and Jon likely were cautious in the immediate use of the dragons because NK already shrewdly claimed one and could do that again. Also, they knew he was lingering on Viserion somewhere.
Dothraki fight like a mindless mob. Once their swords were set aflame, they were like a pack of wild dogs. Even Ghost joined the charge.
The teaser for the next episode showed both dragons and Ghost survived.
Bran is mostly useless but he warged into the ravens who flew directly to NK and basically led him to his death, and not a moment too soon. He knew where to kill NK and Arya used the dagger he gave her at the start of the series, which closed that arc.
When Melisandre told Arya she'd "close blue eyes forever", Arya knew what to do. She snuck up on the wights at the tree like she did Jon. There was even a breeze past one of the lieutenants first. And she used the dagger technique she did against Brienne in training.