Even if Zoya is Sedique's daughter her name is still Faroqui. Because her adopted father or Jiju as she calls him is Faroqui. So the nikaah would have been valid even if they said Zoya Faroque, something they would have said if she married Asad aswell. But the thing that would be a reason for this marrige to not count is firstly both the birde and the groom has to be asked 3 times, less then that and the nikaah is not valid. The qazi asked them once each and khalas??
Secondly Zoyas fathers name was apparently Ahmed something something, and not Farouqui. It could be possible that Zoya has her mothers last name. But it's impossible for the Qazi to know each family member by name and rishta when the family it self lives in the US.
So this isn't a valid nikaah, and both Asad, Zoya and Ayaan knowes this. And this drama they have given the name of a nikaah is only to be until Nikhats nikaah. After that Zoya will return home again..