I need to improve my English skills,Could you give me a hand?
"Who is coming ?" is probably the most usual, but "Who are coming" is perfectly correct, and might tend to be used more often if the inquirer wants to know who each visitor is rather than just getting an answer like e.g. 'some of my friends' or 'most of the rugby team'. Incidentally I take exception to the original question, which I would pose as: "If you know that several people are coming, which question would you use?" or "If you knew that several people were coming, which question would you have used ?"
Sorry- careless typing on my part. I have changed it to 'know'.
If we don see anyone then call them who is .....?