Method of Salaah

Reciting Sami Allahu liman Hamidah instead of Subhana Rabiyal A'laa

Q: When performing Salaah behind the Imaam, in the sujud after saying a few times "subhana rabbiyal alaa" somehow I was about to say "sami Allahu liman hamidah" but as soon as i said "sami Al" I realisized and cutt off and continued saying "subhana rabbiyal alaa". Now was my prayed invalidated since I cutt of at the half? Must I repeat it?

Sunnah method of dua after Salaah

Q: In our area, the Imam starts to make dua with such a voice that muqtadi could know that Imam has started to making dua and all the muqtadis start making dua after listening to the voice of Imam (e.g. if he starts dua with alhamdulillahi rabbil a'alameen, he says alhamdulillahi...... with voice and then make entire dua silently). He ends the dua with voice so that muqtadis could know, and muqtadis also end their dua after listening to his voice. No one starts making dua before and none completes dua before the Imam. What is the shar'ee status of this all described above? Should the muqtadi not start making dua before the Imam? Should the Imam inform the muqtadees about his dua by starting it with voice or he should starts his dua silently? If one has finished his dua before Imam, should he wait until the Imam finishes or one should he stand up to offer the sunnats (if there are sunnats after that fardh salaah)? Please clarify the questions and the Shar'ee status of the custom of dua described above.

Tashahhud of Hazrat Abdullah bin Mas'ood (Radiyallahu Anhu)

Q: Are Hanafi's allowed to pray this Tashahhud:

التَّحِيَّاتُ لِلَّهِ وَالصَّلَوَاتُ وَالطَّيِّبَاتُ السَّلَامُ عَلَى النَّبِيُّ وَرَحْمَةُ اللَّهِ وَبَرَكَاتُهُ السَّلَامُ عَلَيْنَا وَعَلَى عِبَادِ اللَّهِ الصَّالِحِين. أَشْهَدُ أَنْ لا إِلَهَ إِلَّا اللَّهُ وَأَشْهَدُ أَنَّ مُحَمَّدًا عَبْدُهُ وَرَسُولُهُ.

Congregational Dua

Q: One person who has ta'lluq with the salafees told me that making dua with jamaat after salaah is not established. Therefore we shouldn't make it in group. Rather each one should make his dua separately.