Zikr and Dua After Salaah

Q: Is dua after Salaah and facing the congregation a sunnah? Please elaborate.

Q: In Nizamuddin markaz we have seen that the Imam saheb does not make dua after salah with congregation and we make dua individually but in other masaajid the imam makes very short dua with congregation. Which one is sunnat?

Q: Is it a Sunnah after fardh Salaah to read Allaahu Akbar once and 3 times astagfirullah. The Third astagfirullah should be recited audibly and pull on laah?

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.

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.

Q: After the fardh salaah, I know according to the hanafi madhab the tasbih-e-fatimi, ayatul kursi etc should be read only after the sunnah-e-muakkida. However, if I end up forgetting or getting distracted after sunnats and find it easier and can be more punctual in recitation after the fardh immediately, and then after that read sunnats, is this permissible?

Q: If we perform a fardh salaah which have sunnah muakkadah after it (zuhr, magrib, isha), when should we read dua after salaah? After the fardh salaah or after the sunnah muakkadah salaah, or after both?

Q: It is mentioned that a person's dua will be answered if he makes duaa after the fardh salaah. Does this mean that he should make dua after the fardh of the salaah or after the entire salaah is completed?