In the Name of God, the Most High

1- There is no problem in reciting a dua after the opening chapter of the Quran but the obligatory precaution is to avoid saying “Aamin” especially in congregational prayers, though one might say it as ‘dua’. In fact, if a person says “Aamin” unintentionally, it will not render the prayer void.

2- Sufficing to reciting Al-Hamd in the first two Rak’ats (units) or reciting a part of the Sura along with Al-Hamd in obligatory prayers in the state of freedom is not free of reason, although it is against precaution and fatwa of most scholars but it is makrooh (abominable).