"How many women and men are standing at the bus stop?"
Translation:Hány nő és hány férfi áll a megállóban?
No, you do not have to repeat "hány", it is only for emphasis. One is enough usually. Unless there is something between the two countable parts and you say it again, to clarify:
"Hány nő áll a megállóban és hány férfi?" - somewhat unusual but correct.
To answer your question: yes, your version is also possible.
I just thought of something. You might want to know both the number of women and the number of men, separately. Not just the total. In that case, you definitely repeat the word "hány".
I guess it is similar in English. "How many women and men ..." is not necessarily the same as "How many women and how many men ...".
It is especially clear when the answer comes:
"Five women and men" vs. "Five women and five men".
If you have a question with a question word, you want to put focus on the part that's asked for. In this case, you're interested in the number of men and women. Thus, the verb, which determines the focus, needs to be put right after the question phrase: "Hány nő és férfi áll..?"