Question: If Diana was able to recognize Kit even after years of not seeing him then how come she didn't notice he has the same voice as the Phantom, whom she had just been with the day before? He doesn't try to disguise his voice in any way.
Question: What kind of police motorcycles were used in the movie?
Chosen answer: Two were used. A 1936 Harley Davidson knucklehead, and mid to late 40's Indian Chiefs.
Question: What exactly caused the volcano to explode at the end? It didn't seem active at all and it just decided to blow after Phantom and Diana escaped the pirates.
Chosen answer: The explosions from the skulls and the weapons on the island caused the volcano to erupt.
Question: Is Quill actually a member of the Sengh Brotherhood or does he just have the spiderweb tattoo for protection in case he encounters them, as happens towards the end of the film?
Answer: No, he was a member, they most likely had different branches scattered all over the world.
Answer: She was preoccupied trying to escape from the bad guys and annoyed that a guy in a purple suit, was trying to save her, when she said, "I can do it myself." It was most likely later, in New York, when the met face to face. Kit and Diana, when she put two and two together. Again was too preoccupied trying to save the world to pause and confront him.