Here "city" refers to the people. The city is spoken of as if it were a container. And, "confusion" is spoken of as if it were the contents that filled the container. Alternate translation: "Then people all over the city became upset and started shouting" (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-metaphor]])
The Ephesus theater was used for public meetings and for entertainment such as plays and music. It was an outdoor semi-circular area with bench seats that could hold thousands of people.
# Paul's travel companions
The men who had been with Paul.
# Gaius and Aristarchus
These are names of men. (See: [[rc://en/ta/man/translate/translate-names]])