Method of Salaah

Q: Do we need to recite surahs in order as per the Quran Majeed?

If a person doesn't know this ruling before and afterwards he comes to know it, he recites in order, what is the ruling on this?

Q: In some coutries, ulama say that zikr (like Lailaha illahu wahdehu la shareeka lehu... zal jadda minkal jadd) which is done after prayers with loud voice is sunnah. We have never heard our ulama or Imamas in Pakistan doing zikr after prayers with audible voice. Can you please guide what is Sunnah?

Q:

1. Can one read multiple duas that come from the hadith after tashahud and before tasleem?

2. Can one read one dua multiple times after tashahud and before tasleem like: Bismillahi ala dini wa nafsi wa waladi wa ahli wa mali Or Allah humu ini aoothbika minal mathami wal magram?

Q: I was confused when exactly should one say "Rabbanna wa lakal hamd". Is it when you rise from bowing immediately or after you put your hands down and stand for a short while before going down? 

Q: I prayed asr with an imam. When I was in sujood, the row was tight and my elbows were touching my knees. If I remember correctly, I heard somewhere that you should not let the elbows touch your knees but rather spread them out. But is it essential for prayer to be valid?

Q: During salaah, due to anxiety/anger because I heard someone in my family making unnecessary loud noises, I raised my voice in recitation a little. Is my prayer valid?

Q: In a few of my past prayers, I remember I had moments where I’d get confused or make a mistake during prayer due to being nervous and in those moments I’d cough or sniffle without necessity, as a result of embarrassment and me not wanting anyone around me to think that I was struggling during salah. Do these salah’s need to be repeated?

Q: I heard in salah, errors to do with waqf dont matter. Does this apply to stopping in the middle of a word and then resuming?

I attempted reciting waladhaleen twice and every time between the ‘leen’ part, my voice stopped because of an obstruction in my throat. However, the third time I tried again and the same thing happened, after the pause, my voice came back a second later and finished reciting the remaining letters. Because I paused abruptly, is my salah fine?

Q: Is it compulsory to recite 'wajjahathu wajhiyya...' in the starting of sunnah prayer and "allahumma ighfirlee maa qadhammthu..." in the tashahhud of sunnah prayer.

Q:

1. I recited ‘saliheen’ with a bottom throat ‘ha’ and noticed during the middle of reciting it during the enlongation of the last syllable. During the elongation of ‘heen’, even after I realised, I still pronounced it with my lower throat. Is this considered intentionally reciting something wrong and did it invalidate my prayer?

2. During the du’a portion of Witr, I usually recite Rabbana Atina Fidunya 3 times. The second time I recited it, it felt like I had recited ‘Rabbana atina fidunya hasanatan wa qina adhabanar’ as opposed to the correct full invocation. Because of my uncertainty, can I assume my prayer is sound?