Ghair Muqallidin (who call themselves Ahl Hadith) are deviant and out of the folk of Ahl Sunnah al-Jamah as they differ from Ahl Sunnah wal Jamah not only in Furoo (derivative issues) rather in Usool (fundamentals). (For more details see Rahmatullah al-Wasiya, Vol. 2, p. 740-744)
The nikah of a Hanafi girl is valid with a Ghair Muqallid boy as they are Muslims though ghair muqallidin are deviant, but due to other various reasons one should not establish marital relations with them.
Allah (Subhana Wa Ta’ala) knows Best
Darul Uloom Deoband