Musjid extension

Q: Our Musjid, has gone through an extension on the left side, However there is a separating wall (not completely separated few rows the an entrance, and few rows again) in between the Original Musjid and the extension. The extension is used for itikaf and is part of the Musjid. Usually on Jumma or when the musjid gets full the extension is used. The set up is similar to Musjidun Nabawai alhis salam. where outside the the front row continues, separated by walls:

  1. Is the reward the same when standing in the front row,between the separating walls?
  2. Should the original Musjid be filled 1st, then the extension or vice versa?
  3. Can I stand alone in the extension to get the reward of filling the front rows?

Raising the hands for Dua in Salaah

Q: In Arabian countries "Dua" will be recited by the Imam in gathering by lifting hands after "Dua-e-Qunoot" (before going for ruku') in "Waib-ul- witar" Prayer during Ramzan, in particular and before going for Rukuh of third Rakahat of Maghrib Prayer in general and why this procedure is not practiced in India, Kindly enlighten this.

Repeating the salaam because of doubt

Q: If one prays behind the imaam, and after the imaam has finished both taslims the congregation gives the taslim to both sides (this is the custom method in the masjid I am going thus I also follow this) If after the imaams both taslims, I do give taslim to the right side and then to the left side, but I do repeat the taslim to the left side (because of a doubt that I didn’t hear myself saying a small portion of the taslim). 

Did this break my salaat? Did I had to do sajdah sahw or what did I have to do? Is my salaat complete. I didn't repeat it, if I have to repeat it when must I repeat, is this after 5 salaat times are past away since the the order is waived and the salaats after the salaah which has to be repeated are then valid and no need to repeat those salaats also?

In such case is there a circumstance that the taslim to leftside is considered delayed and thus must be sajdah sahw? Or does it not so count since I did it because of a doubt ? In case that the first taslim I thought I had not heard a portion of it, was done correctly, does the addition of the repeating change anything, or is it not to be considered since I am then already out of salaah and nothing matters what I do say after the taslim to the leftside?