Are the mentioned books accredited in the Hanafi school and is it permissible to issue fatwas based on them?

The books mentioned (Radd al-Muhtar, Maraqi al-Falah, Kanz al-Daqa'iq, Fath al-Qadir) are considered authoritative and beneficial texts, commentaries, and supercommentaries among the Hanafis. The primary texts (mutun) and some of their commentaries are given precedence over books of fatwas (legal opinions) when there is a contradiction. Al-Mabsut by Al-Sarakhsi is a very important book among the Hanafis and is given precedence over others. The six books of Zahir al-Riwayah (Al-Mabsut, Al-Ziyadat, Al-Jami' al-Saghir, Al-Jami' al-Kabir, Al-Siyar al-Saghir, Al-Siyar al-Kabir), authored by Muhammad ibn al-Hasan al-Shaybani, are the fundamental source for the Hanafi school, and what is found therein is preferred when there is a difference in legal opinion.