Is this just a random phrase to help us learn or would it translate as:
"Who is having the fish?"...like a question a waiter would ask a group in a restaurant?
Your option is also suitable...
The voice that pronounces the sentence pronounces "Quem" differently than the voice that pronounced the word when tapped/clicked. One says (keem) and the other says (kweem). Are both acceptable?
No. In this case, it is only /keem/. You don't pronounce the letter u.