Qiraat

Q: How long does the Aa in Aameen have to be stretched for?

Q:

1. I have been told that if, for example one reads surah Nasr in the first rakaat, then in the next rakaat one cannot read surah Ikhlaas - it has to be the next surah, or a gap of 2 surahs. Please clarify this rule for me (e.g., does it apply only to short surahs, does it apply to 4 rakaat salaah as well, etc.)
2. For long surahs, can one read from different parts of the surah in consecutive rakaats. Eg., 1st rakaat beginning verses of surah Najm, and 2nd rakaat ending verses of surah Najm.

Q: Question regarding reciting inaudibly. In my case I was praying Dhuhr Fardh and quietly as to hear my own voice, in my last (4th rak'ah) - I was reciting "Ghayril Maghdoubi" at Maghdoobi, I could only clearly hear "Ma--doobi" the Gha wasn't proper so that I could hear, but I moved my tongue to recite it as normal. Obviously I didn't want to recite "Ma--doobi", so I think I inaudibly said the gha, does this matter or affect the validity of the namaz?

Q:

1. Can I say Ameen feebly (not bil jahar) or is it compulsory as I live in a Hambli environment?
2. Is doing of rafa ul yadain compulsory? Can one leave it curtesy living in Hambli environment?

Q: When I perform Salaah alone, should I recite Bismillahir Rahmanir Raheem before Surah Fatiha in every rakaat of Salaah? Also, should I recite Bismillahir Rahmanir Raheem after saying Aameen and before I start another Surah?

Q: If in "Ihdeenas-Siratal-Mustaqeem", I recited dee with a daad mistakenly instead of daal does this invalidate the namaz? I don't know for sure if I done it, but it seems likely so should I repeat the namaz or is it an acceptable mistake? I didn't repeat it afterwards.

Q: Assuming in the first rakaat of witr, one recites Surah Lahab and Surah Ikhlaas in the second rakaat. Is it necessary to make sajda sahu as only Surah Falak or Surah Naas can be recited in the third rakaat but these Surahs are longer than Surah Ikhlaas. Likewise, in any other namaaz, if one recited a Surah in the second rakaat that is slightly or much longer than the surah recited in the first rakaat, what is the ruling?

Q: When one is performing Salaah, is it necessary for one to hear his own voice and whatever he is reciting?

Q: I started praying magrib alone before another brother joined me, so during the second rakaat I recited only one verse from the Quran (sura ghafir verse 44) after fatiha and went to ruku position. Since then I have been having doubts if my salaah is valid or not. If not what should I do because that brother is gone now. 

Q: I read a book called Umdat ul Islam written by Abdulaziz bin Hamidullah in Persian some 700 years ago that if one reads the word hamida of sami Allahu liman hamidah with the letter ه instead of ح the salaah becomes faasid. Is this correct, it was also written that if you read Allahumma salli, the word salli with a س and not a ص the salaah is faasid. 

The book in question is it a authorative book? It says also some strange things like that in Jami al Fatawa it is said that if a person makes zina with a animal the animal should be killed and burned, and the person should also burned or a wall should thrown on him.