sunnat salaah

Forgetting to recite a Surah in the third rakaat of Sunnat Salaah

Q: I performed the four sunnah of Asr salaah however in the 3rd rakaat I forgot to read a Surah after Surah Fatiha only realised this in ruku. I intended to make sajda sahwa but after the 4th rakaat I read the tashahud, durood and dua and made both salaams. Whilst making the second salaam I remembered the sajda-e-sahw and immediately made a sajda after then completed the Salaah. Was I correct or did I have to repeat the Salaah?

Is it permissible to perform the Sunnats of fajr after the fajr Salaah?

Q: I woke up for fajr and thought there was not enough time to read the sunnahs, so I read the fard. After completing the fard, I realized there was still time left, so I read the sunnahs of Fajr after praying the fard of Fajr, within the time of Fajr. are the sunnahs valid? Or will I need to redo them after sunrise?

Going late to the Musjid for zuhr Salaah

Q: I am at home and the zuhr prayer jamat will soon start in the masjid and I have only a few minutes to perform my 4 sunnats. If I perform the sunnats before I leave for the masjid, I will miss the beginning of the jamat (I will catch the last 1-2 rakats). Should I do this, or should I instead leave early to the masjid and pray the 4 sunnats after the fard, thus catching the jamaat from its beginning?

Performing the Sunnats of Jumu'ah after zawaal

Q: I stay in Cape Town and most of the musjids are of the Shafi'ee Mazhab. For the Jumuah Salaah, they only perform two rakaats sunnah before the second Azaan and khutbah commences. Since I am of the Hanafi mazhab, I am required to perform four rakaats. Therefore I am not given enough time to complete it and generally I am in the third or fourth rakaat of my Sunnah Salaah when the Azaan or khutbah starts. Kindly advise me of the correct procedures to be followed if what I am currently doing is not acceptable.