Salaah

Nafil Salaah in jamaat

Q: Qiyaam-ul-layl: I am a Hanafi  living in an area where, unfortunately, many do not follow a set mazhab. One of the brothers requested that 'Qiyaam-ul-layl' be performed in jamaat during Ramadaan. From his description, I understand this to be tahajjud salaah (as we have already
arranged for Taraweeh salaah). Is it permissible to perform any nafl salaah in jamaat?

Repeating Surah Faatiha in Salaah

Q: One read more than the half of surah al Fatiha in the 1st rakah, then doubts whether he recited the beginning part correctly. If he re-starts from the place he doubts (and thus repeats a half or more of the whole surah) does he need to do Sajdah Sahw? Thus does repeating a half or more due to a doubt whether one recited correctly or not necessitate sajdah sahw, or does sajdah sahw become waajib only if one forgetfully repeats a half or more?