Sajda-e-Sahw

Q: If in a 2 rakaat prayer one does forget to read a surah after surah al Fatiha in the 1st rakaat, should he read two surahs in the 2nd rakaat after surah al Fatiha? If yes, is this Waajib to do so, and what if one wilfully does not do it?

Q: An Imaam said Allahu Akbar in stead of Sameallah who liman hamedah. He did not make sajdah sawh. A brother got angry and made him repeat the salah. The Imaam was not present on this day hence the chaos. My question is this:

1. Was sajad sahw necessary?
2. Does the salah go through with out it?
3. Did they have to repeat the salah?

Q: 

1. In salaah I was reading a surah after surah fatiha. As I was reading it I wasn't sure if I read my surah fatiha, so I started from the beginning with surah fatiha. Is my salaah accepted?
2. In the future if I forget if I read surah fatiha what should I do? Should I make sujdah sahu , or as above?

Q: After reading a fatwa on islam-qa I am somewhat over concerned cautious in doing the takbirat, tasmi, tahmid inbetween the postures, and I mostly end up doing sajdah sahw as precaution. What is the solution for me?

Q: If I, after having read a short bit of sura whilst praying, forget the remainder of the sura, and change to reading another sura in order to fulfil the wajib amount of qira'a, do I have to do sajda sahw?

Q: What is the case if one recites in his Salaah:

1. Surah fatiha (right after one another) twice in one of the first two rakats.
2. Surah fatiha after the surah one has read after surah fatiha.
3. Surah fatiha twice in the last two rakaats.
4. At-tahiyyaat twice in the first sitting.
5. At-tahiyyaat twice in the last sitting one after another.
6. At-tahiyyaat again after the durood ibrahimiyyah
7. Durood ibrahimiyyah one after another.

In which cases one must repeat the prayer as makruh tahrimi act was carried out?

Q: If the follower (muqtadi) intentionally omits a necessary action (wajib) or intentionally commits an action that is prohibitively disliked (makruh tahriman) while praying behind the imam, is it necessary (wajib) for him or her to repeat the prayer? Things like leaving out at-Tahiyyaat, or reciting behind imam, reciting at-Tahiyyaat twice etc.

Q: I read that if after the salaam of the salaat a makruh time enters and there was a sajdah sahw to be made, then one is absolved from doing sajdah sahw. But he must repeat the whole salaah. For example, if after the salaam in Fajr the sun has risen, then one should not do sajdah sahw, but he must repeat the whole salaah later on. The same counts for Asr when after the salaah the makruh time enters (i.e. after the suns rays become yellow/orange meaning when one is able to look at the sun without being dazzeld). Is this true ? The same ruling would apply to someone who forgot the sajdah sahw, or lost wudhu after salaam before the sajdah sahw.

Q: Can you explain how sajda-e-sahw is done in the Hanafi Mazhab?

Q: In the third rakaat of magrib after surah fatiha I mistakenly read bismilah hir rah manir raheem (not all of it). Is my salaah valid?