Is it legislated for the congregant to invoke blessings upon the Prophet aloud, or to say "balā" (yea) or similar expressions, when the Imam recites verses of glorification, supplication, or the verse: "Indeed, Allah and His angels send blessings upon the Prophet," or "Is not Allah the most just of judges," in obligatory and supererogatory prayers? And is the response that indicates a difference of opinion among scholars, based on three views, correct? What are the evidences and schools of thought for each view?

What the questioner mentioned is close to being correct, as the majority of scholars have affirmed the permissibility of remembering Allah (dhikr) when passing by a verse that necessitates it for the worshiper (whether an Imam, a follower, or praying alone). This includes saying "Subhan Allah" (Glory be to Allah) when passing a verse of glorification, seeking refuge (isti'adha) when passing a verse of seeking refuge, and asking (du'a) when passing a verse of asking. Their evidence for this is the hadith (definition) of Hudhayfah. Al-Nawawi transmitted the view of the Hanafis as disliking this, while Sheikh Al-Uthaymeen elaborated, giving a fatwa (definition) of its permissibility in supererogatory (nafilah) prayers and its allowance in obligatory (fard) prayers.