Answer
(Fatwa: 891/565/L=1432)
If the witnesses are aware of it and they know the girl, nikah shall be valid by replacing the name of father with the name of the person who has adopted her in Nikah papers. However, it is not right to write the name of other person in place of her real father. Instead of the name of any other person, the name of her real father should be written in Nikah papers:
قلت وظاهره انها لو جرت المقدمات على معينة وتميزت عند الشهود ايضا يصح العقد وهو واقعة الفتوى لأن المقصود نفى الجهالة وذالك حاصل بتعينها عند العاقدين والشهود (شامى).
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband