All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
There is no harm on the lay-Muslim to act upon the fatwa of the scholar and follow his opinion even if it is contrary to the four Mathhabs. The lay-Muslim is not required to ask the scholar whether his fatwa conforms to the four Mathhabs or not. In fact, Muslim scholars have been issuing their fatwas and opinions that they believed to be most likely correct even if they were contrary to the four Mathhabs. Shaykhul-Islam Ibn Taymiyyah for example, held views contrary to those of the four Mathhabs in famous issues, and a great number of scholars agreed to his views on those issues.
We have previously underlined in fatwas 84248, 83321, and 81976 that Islam is not confined to the four Mathhabs and that the Muslim is basically allowed to follow the teachings of the Quran and Sunnah if he is qualified to deduce the rulings on the different Fiqh issues directly from them; otherwise, the lay-Muslim, who lacks the sufficient knowledge and qualifications to deduce the rulings from the religious texts himself, should follow the views of his scholar (whom he trusts and consults).
Some scholars held that it is impermissible for Muslims to follow other than the views of the four Mathhabs, such as Ibn Rajab who wrote a treatise on this topic entitled Ar-Radd ‘ala Man Ittaba’ Ghayr Al-Mathaahib Al-Arba‘ah.
Allah knows best.