Sajda-e-Sahw

Q: I have few questions regarding my doubts and sajdah-e-sahw

1. If I performed sajdah e sahw already and then I recited attahiyaat again and committed mistake in the second part of the shahada i.e. (wa ash hadu anna Muhammadan abduhu wa rasooluh) but not corrected and go to durood shareef and while reciting durood remember that I committed mistake in shahada so I just recited the second part of the shahada again and then recited the durood again, is it permissible to recite the mistaken part only or do I have to recite the full shahada again once I reach durood shareef ?

2. If I repeat any ayat of Surah Faatiha, not the full surah or any part of attahiyaat and not the full attahiyaat, does sajda e sahw become wajib or not?

Q: If one is performing 2 rakaats sunnats of fajr or isha, and he stands up after reciting tashahud in qaidah forgetfully for the 3rd rakaah, what should he do and recite when he sits back down in qaidah?

Q: If I wanted to read 2 rakat of nafl salaah but after reading 2 rakats, without sitting, I get up accidentally, should I break my salah? If I sit for tashahud but forget doing salam and get up accidentally what should I do?

Q: I offered Isha prayer, but recited tashahhud between the two sujud in my second rakat. I decided to do sajdah sahw, but I forgot and completed my prayer. I was still facing the qiblah, but I removed my eye glasses, wiped my face and muttered to myself. Then I remembered to do sajdah sahw, and did it. Should I have done sajdah sahw? Will I have to repeat my prayer? 

Q: While reading the witr salaah and in the last rakaat if I forget to read the qunoot but remember when I go into ruku wat should be done?

Q: I had missed one rakah in Isha jama'at. When I was offering the missed rakah, I forgot to recite a surah after al faatihah. I realised this and made Sejdah Sahw in the end. Should I repeat my prayer.

Q: Is Salaat valid in the following cases? If so, please advise what should be done if such an error occurs in the Salaat.

1. Mistakenly reciting thana twice.

2. Mistakenly reciting some Ayaats of a Surah, or an entire Surah, instead of tashahhud. Tashahhud is then recited after the mistake is  realized.

3. Mistakenly reciting some part of tashahhud, or the entire tashahhud, instead of Surah Fatiha. Surah Fatihah is then recited after the mistake is realized.

Q: A person missed one rakaat in fardh salaah. At the end, when the Imam made salaam, the person who missed the rakaat made the salaam, either to one side or both sides. Does he need to make sajda-e-sahw for the salaam he made with the Imam?

Q: What should we recite in sajda e sahw?

Q: If someone is performing zohar farz salah and in the last rakat after tashahud (attahiyat), he stands and after completing the sajda if the 5th rakat, he remembers that he made the mistake in this condition. What should he do and how should he complete his farz salah?