attahiyyaat

Q: If a person left out a portion of tashahud (At-Tahiyyat) in Salaah, does he have to make Sajdah-e-Sahw? 

Q: If a person because of some disturbance missed an Aayah in Surah ​Faatihah, or one sentence in his At-Tahiyyat, does he have to make Sajdah-e-Sahw? To what extent is the Surah Faatihah and At-Tahiyyat Waajib?

Q:

1. If one happens to omits portion of Durood Ibraaheem due to one forgetting it or making a mistake, is the Salaah valid?

2. If one happens to recite Tashahud and one repeats the portion( Ash Hadu...) where the index finger should be raised, perhaps due to getting stuck, should one raised the finger twice?

3. If yes, and it was not raised twice, is the Salaah valid?

4. Whilst in Salaah, during Durood Ibraaheem, one adds the words "Sayyidina" before the words and Names Muhammed (Sallallahu Alaihi Wassallam) and Ibraaheem (Alayhis Salaam), is the Salaah valid?

Q:

1. If the Imaam in taraweeh salaah mistakenly sits down for tashahhud after one rakaat, thinking it to be the second rakaat. After sitting down, he immediately realized and stood up for the second rakaat. In such a case, will he have to make sajdah sahw?

2. And what about if this happens in farz Salaah?

Q:

1. Dua I read in tashahud is: Attehhiyyatu, attayibatu, assalavatu, azzakiyyatu Lillahi. Assalamu ala nabiyi va rahmatalluahi va barakatuhu, assalamu aleina va ale ibadillahi ssalihin…. I read it was narrated by Aisha (Radiyallahu Anha) that after the death of our Nabi (Sallallahu Alayhi Wasallam) this dua was recited. Could you please tell me how authentic this hadeeth is?

2. Can I be reading this dua instead of assalamu aleyka ayyuhen nabiyu…. If I feel inside of me that I am calling to Nabi (Sallallahu Alayhi Wasallam) and it gives me waswasa that I am making shirk? Will my salah be valid in shaa Allah? And if I have no waswasa but just like this dua more because it gives me no doubts and there is no direct addressing to Nabi (Sallallahu Alayhi Wasallam), is it ok to read it?

3. I like to read Surah ikhlaas in the first two rakahs of fard namaz and in all rakahs of Sunnah namaz. I absolutely love this Surah and I know hadeeth that someone also always read it in all rakahs and nabi (Sallallahu Alayhi Wasallam) said that Allah also loves you for loving this surah. Can I continue doing so in shaa Allah? Please explain why you say it is makrooh so I can explain to my friends too?

4. In case your answer is negative in 3, can I be reading in the first rakah - surah fatiha, ihlas and first verse of falaq and in second rakah – surah fatiha and Ihlaas? I know so far - fatiha, ihlas falak, nas and ayat al kursi. But I hope in shaa Allah to read ihlas in all rakahs is not a problem, please kindly answer.

Q: If I say assalamu aleika isntead of wassalamu aleika ayyuhan nabiyyu in my tashahud, so AS instead of WAS.. are my all salahs valid or to be repeated? If during salah I realise I did this mistake again should I make sajda-sawh?