What is the ruling on seeking refuge from Hellfire in the final sitting of the prayer, with a clarification of the evidence of those who disagree and a refutation thereof, and what is the evidence for the prophethood (or pillar-status) of sending blessings upon the Prophet (peace be upon him) in the final sitting?

Seeking refuge from the punishment of Hellfire is prescribed in the final Tashahhud, based on the Prophet's (peace and blessings be upon him) saying: "When any of you makes the Tashahhud, let him seek refuge with Allah from four things, saying: 'O Allah, I seek refuge with You from the punishment of Hellfire, and from the punishment of the grave, and from the trials of life and death, and from the evil of the trial of the Antichrist (Al-Masih Ad-Dajjal).'" The Zahiris consider it obligatory, while the majority consider it recommended.

As for sending blessings upon the Prophet (peace and blessings be upon him) after the final Tashahhud, it is a pillar according to the Shafi'is and Hanbalis, and a Sunnah according to Abu Hanifa, Malik, and the majority. The evidence indicates that it is not obligatory.