Qa’dah and Salaam

Q: Is it permissible to recite Surah Fatiha at the time of tashahhud if you don’t know what to say.

Q: What is the correct way of tasleem in namaz. What I know is, at the end of salah, should I start saying salam (assalamu alaikum wa rahmatullah) when my head is towards the qibla and continue saying salam while I turn my head towards the right and complete saying salam after I complete turning my head. This completes the first salam. Should I turn my head towards the qibla then I should start saying salam when my head is towards the qibla and continue saying salam while I turn my head towards the left and completes saying salam after I complete turning my head. This completes the second salam.

I have observed the following three cases in case of three imams who are leading prayers. Could you please clarify if the salah is valid in these cases.

1. At the end of salah,the imam turns his head towards the right and after completely turning he says salam. Then he turns his head to the left after completely turning he says second salam. Is salah valid in this case? Why I am asking this question is , I have read somewhere (I guess it is from a shia person) that if you turn your head during salah your salah will become invalid. In this case the imam first turned his head to the right, by the time he starts saying the salam his salah has already become invalid.

2. The imam completes the first salam properly as per my understanding. But he starts saying the second salam when his head is turned towards the right and continue saying the salam while he turns his head towards the left and completes saying the salam after he completes turning his head towards the left. Is salah valid in this case?

3. At the end of salah, the imam completes saying salam when his head is towards the qibla then he turns his head towards the right. Then he turns his head towards the qibla and completes saying salam when his head is towards the qibla then he turns his head towards the left. Is salah valid in this case?

Q: I don't know the last durood that is read in last before salaam. What can I read inplace of that? I also don't know the dua in witr salaah. What should I do? 

Q: Please can you tell me if my salah is valid if I forgot to say takbeer after the first tashahud and did not perform sajdah sahw.

Q: Do we need to move the finger or just raise it while reciting tashahhud? 

Q: Can we read "rabbana hablana min azwajina.....imama" and "rabana aatina fidduniya hasanah......waqina azab-al-meezan" in namaz after durood and before salam?

Q: What if a person makes a mistake in the first salam of salah (i.e changes ح to خ) and without correcting it moves to the second salam, is the prayer valid?

Q: Is the following commonly recited dua after durood thabit?

اللهم اغفرلي و لوالدي و لأستاذي و لجميع المؤمنين و المؤمنات و المسلمين و المسلسلات برحمتك يا أرحم الراحمين

Q: I just want to ask when performing the tashahhud, when will I raise my finger and when should I place it down? 

Q: Can I read the following dua in my salaah? (Eg in sajdah, end of tashahhud)

توكلت على الحى الذى لا يموت الحمد لله لم يتخذ ولد و لم يكن له شريك فى الملك و لم يكن له ولى من ذل و كبره تكبيرا