I wrote "these guys" instead of "these men" and duolingo did not accepted it. Can anyone confirm if this is wrong?
It's not wrong, but it's colloquial.
Also, I was told that 'guys' can refer to both men and women nowadays.
Couldn't 'czy' be translated as 'whether' in this sentence? It was not accepted.
That should have already been accepted.
What is wrong with: "These men asked if I am a driver."
Nothing is wrong; it is a correct and accepted answer.
If we start with czy it is the question sentence
Correct. However, this sentence starts with "Ci" not "Czy".