Jamaat Salaah and Imaamat

Second jamaat in the musjid

Q: If due to rain in certain parts of the world, Maghrib and Isha’ are prayed together in the masjid. Would it be permissible for Hanafis to conduct a second congregational Isha’ prayer in that masjid, because it is forbidden to conduct second congregation prayer in a masjid?

Masbooq in witr salaah of Ramadhaan

Q:

1. In Witr Salaah in the month of Ramadhan, if the masbooq joins the Imam in the ruku of the last rakat, is it wajib for the masbooq to recite dua e qunoot when he stands up to complete his missed rakat and in which rakat will he recite dua e qunoot?

2. In Witr Salaah, if the masbooq missed all the rakaats and did not recite dua e qunoot when he stood up to complete his Salaah, is it compulsory upon him to repeat the Witr Salaah after the Salaah time has expired?

3a. If the masbooq turned for salaam with the Imam accidentally or not knowing the masala and he did sajdah sahw at the end, is the Salaah valid?

3b. In the above situation, if he didn't do sajdah sahw, is it compulsory to repeat the Salaah when the Salaah time has expired or is the Salaah valid but incomplete?

4a. When the Imam did salaam to do sajdah sahw, the masbooq accidentally or not knowing the masala, he also turned his head for salaam and then did sajdah sahw at the end of the Salaah, is the Salaah valid?

4b. In the above situation, if he didn't do sajdah sahw, is it compulsory to repeat the Salaah when the Salaah time has expired or is the Salaah valid but incomplete?

What should a masbooq recite when standing up for missed rakaats?

Q:

1. Suppose I am offering Asar or Maghrib and I joined the Namaz in the last Rakaat after missing the first three rakats, now when the prayer ends with "Assalaamu alaikum warahmatullah" by Imam and I get up from "Attahiyyaat", Then what do I have to say first? Do I have to start my next rakat with thana or bismillah?

2. Also, do I have to say a surat after reciting surah fatiha?