Is it obligatory for the congregant to recite Al-Fatiha and what is easy of the Qur’an, or is the recitation of the Imam sufficient in congregational prayer? And what is the ruling on the middle Tashahhud after the two Rak'ahs and what is said therein?

The rulings regarding the congregant's recitation of Al-Fatihah are summarized in Fatwas No. 31199 and 41880. It is permissible for the congregant to recite what is easy for him from the Quran after Al-Fatihah in the silent prayer, but it is not permissible for him to do so in the audible prayer. As for the first tashahhud and sitting for it, they are two sunnahs according to the majority of scholars, and two obligations according to the Hanbalis. The wording of the tashahhud was mentioned in the two Sahih collections, and it is famously known as the tashahhud of Ibn Mas'ud. Al-Shafi'i preferred the tashahhud of Ibn 'Abbas due to its additional wordings.