salaah

Mistakes in taraweeh salaah

Q: With regards to Taraaweeh:

1. An Aayah was recited correctly. The Imaam thereafter repeated the Aayah and changed it (incorrectly) due to some doubt. Is the initial correct recitation or the second recitation which was incorrect taken into consideration? Does the Aayah have to be repeated?

2. For the purpose of listening to the Luqmah of a Saami', the Imaam remained silent for the duration of 3 Subhaanallaah or more (he did not recite Qiraat for that duration). Should Sajdat-us-Sahw be made?

3. Additionally, 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 Sajdatut-us-Sahw? To what extent is the Surah Faatihah and At-Tahiyyat Waajib? 

Will a person qualify as a musaafir if he travels safar distance weekly from his home town?

Q: From last four years, every week Monday I travel from my native town to 150 KM for work (working in IT company) and I stay there till Friday evening, I stay with my friends in a rental house, then I return to my native town by Friday night, and I stay in my native town till Monday morning. My question is that while I stay in my working area (i.e. Monday morning to Friday evening) whether I have to shorten my prayer or I have to pray regularly (i.e. four rakaats)?